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Old 04-21-2011, 05:31 AM   #1
petey-pablo
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BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

I have a quick question My under dash wire harness burnt a couple of months ago I finally got around to replacing it with a new wire harness I spent over $300 for it.. Drove it for the first time the other day and the same thing happen.. The wire that is burrning up is The BROWN WHITE Striped wire from the Ignition switch to the fuse block Any one have any idea of what can be causeing this? I bassicly went through all my wiring since I replaced it but found nothing that could be causing this.. The truck was running fine with no problems prior to the first time it burnt. I cant remember if I did anything prior to this to cause the problem I did change out my fans and wired them up but I dont see how this could have caused it.. I will be checking over my alternator wiring again tomorrow.. Any thoughts of what can cause this or help would be greatly appreciated thanks Pablo....
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Old 04-21-2011, 07:18 AM   #2
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

bad dirty connections and bad dirty ground path can cause excess heat due to poor conduction of electricity
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Old 04-21-2011, 12:19 PM   #3
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

The brown/white wire you describe runs from the key switch to the firewall block on the diagrams I have. It is joined there by a solid brown wire that runs back to the cluster plug to pin 8 on the idiot light dash. It is used to feed the alternator field exciting circuit through the regulator.The ammeter dash does not have this wire. On the other side of the firewall block (engine side) it goes to solid brown and goes to the terminal 4 on the external regulator and if the alternator has been converted to internal regulator it runs to terminal 1 on the alternator.

This diagram shows the b/w wire from the key switch.

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This one shows it continues to the firewall block, joining with the other brown wire to the cluster plug.

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Here is the alternate view of the brown wire going from the key switch to the external voltage regulator.
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Here is the conversion diagram. It shows the diagram with the idiot light and the Accessory wire feed to the fuse panel is left out but it still is in the circuit.

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Now if some one has converter the alternator and ran a separate wire maybe they just cut the stock wire off and left it hanging and it may be touching a ground. This wire is hot from the key and is not fused except by the fusible link near the battery. It is small enough to burn before the FL in any case and the burn would start nearest the hot source and continue to the ground.

If you were using this wire to feed the high amp fans without a relay then the amperage draw would be enough to burn the insulation off the wire. You are right to trace the wire from the key switch to wherever it goes. If you replaced it where did you run it to?
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Old 04-21-2011, 02:14 PM   #4
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

The brown/white wire is the field wire for the alternator, what type of alt do you have? I assume when you replaced the wire you didn't install a resistor (type of alt will determine value). the resistor limits current flow to from the alt protecting the regulator or diode trio. Your problem is either a short or over current.

Edit, I see Vettevet posted while I was typing but we are pretty much saying the same thing it would be good to know what type of alt you have.
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Old 04-22-2011, 04:12 AM   #5
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Quote:
Originally Posted by VetteVet View Post
The brown/white wire you describe runs from the key switch to the firewall block on the diagrams I have. It is joined there by a solid brown wire that runs back to the cluster plug to pin 8 on the idiot light dash. It is used to feed the alternator field exciting circuit through the regulator.The ammeter dash does not have this wire. On the other side of the firewall block (engine side) it goes to solid brown and goes to the terminal 4 on the external regulator and if the alternator has been converted to internal regulator it runs to terminal 1 on the alternator.

This diagram shows the b/w wire from the key switch.

Attachment 736112

This one shows it continues to the firewall block, joining with the other brown wire to the cluster plug.

Attachment 736114

Here is the alternate view of the brown wire going from the key switch to the external voltage regulator.
Attachment 736111


Here is the conversion diagram. It shows the diagram with the idiot light and the Accessory wire feed to the fuse panel is left out but it still is in the circuit.

Attachment 736110

Now if some one has converter the alternator and ran a separate wire maybe they just cut the stock wire off and left it hanging and it may be touching a ground. This wire is hot from the key and is not fused except by the fusible link near the battery. It is small enough to burn before the FL in any case and the burn would start nearest the hot source and continue to the ground.

If you were using this wire to feed the high amp fans without a relay then the amperage draw would be enough to burn the insulation off the wire. You are right to trace the wire from the key switch to wherever it goes. If you replaced it where did you run it to?
I am useing a 100amp 10Si Alternator and the wire harness was new and was already converted to use a internal regulated Alternater so I do not have an external regulator anymore. I am running both fans on relays and a separet fuse block all of its own including Electric Water Pump,Electric Fuel pump , and both fans all have relays For each item I bought a relay kit & each fan has it's own relay to wire them up.....

"I have them wired to a Painless CirKit Boss Auxiliary Fuse Block ignition hot and since it has three 20 Amp constant hot and four ignition hot circuits I have the Red wire to constant hot directly hooked up the battery junction block. The ignition activated wire that I am useing to activate this fuseblock with the key on is an extra red wire that was in my Engine Wire Harness on the passenger side this is an after market American AutoWire Engine Harness.. Do you guys think I am over loading this Fuse Block? Painless Part#70207- Provides three 20 Amp constant hot and four ignition hot circuits with a maximum total amperage handling of 40 Amps.
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Old 04-22-2011, 04:25 AM   #6
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

[QUOTE=VetteVet;4637644 You are right to trace the wire from the key switch to wherever it goes. If you replaced it where did you run it to?[/QUOTE]

The first time I did trace it and found nothing wrong with the wire after it left the cab and I figuerd it would be better to buy a new underdash wrire harness So I did. After I installed the new harness the truck started fine for like 15-20 minutes while it warmed up Fans came on then turned it off then started again fine on my way to the Autoparts store It only made it down the street about a block and it started smoking. I traced it againg ripped out all my wiring and went through it one by one and found nothing wrong with the wire after it left the cab So this time around I want to just replace this Brown/white stripped wire I can not afford to buy a whole new dash harness other wise I would.. I have not found the same wire at any aoutoparts stores white stripped brown wire with a single strand of copper inside.Yesterday I took of my Alternator off and I will get it tested today after work Thanks again guys.
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Old 04-22-2011, 09:11 AM   #7
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Quote:
Originally Posted by fixit-p View Post
The brown/white wire is the field wire for the alternator, what type of alt do you have? I assume when you replaced the wire you didn't install a resistor (type of alt will determine value). the resistor limits current flow to from the alt protecting the regulator or diode trio. Your problem is either a short or over current.

Edit, I see Vettevet posted while I was typing but we are pretty much saying the same thing it would be good to know what type of alt you have.
<hyjackie> "resistor" explain please. my truck has been converted to internal reg alt. and the rewire looks "ok" other than the two that you cross at the old reg plug. they just snipped them.
but what is this about a resistor, the alt in it is a basic 63 amp (and 15 volts at idle)
but I have a new 84 t/a ho 96amp waiting..
????????????????

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Old 04-22-2011, 06:25 PM   #8
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Ok guys heres a small update I spoke to a tech from American AutoWire where I bought the harness from via email about my problem and this is what he said "The wire you describe is a resistance (Brown / White Strip) type special wire to excite the alternator. If this wire burned then the alternator must have shorted to ground causing this wire to melt. The wire is stainless steel and can not be soldiered. Please give me a call direct and will discuss your options".
Today I took My Alternator to get tested and it tested BAD.. So they replaced it under warranty. So I talked to the tech from American AutoWire by phone and explained to him my situation again and told him i wanted to fix my wire he offerd to fix the harness for me if I sent it back to them. He also suggested I can go with a 1wire alternator and eliminate that wire completely. So I had my Alternator converted today to a wire. But my question still stands on the fuse block Do you guys think I am over loading it with what I have hooked up to it? I want to be safe because I don't feel 100% positive the Alternator itself being bad could have caused this.. What do you guys think thanks again for the help guys...
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Old 04-22-2011, 07:58 PM   #9
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Well darn.
I saw your post this morning about the wire smoking again and I was going to respond and I had to leave and go to the store.
I see just now that you talked to the tech rep at AAW and he told you the exact same thing I was going to tell you. If you read Fixit-P s post he asked for more information and that is what we really needed from the start. Now that we know what type alternator you have we have a course to follow to help.

The wire that has been smoking is the old resistance wire for the stock 7 gauge truck dash and I posted the diagram above. It is the 3rd one in that post.
I figured you had shorted a diode in the SI alternator and it was pulling too much current through the brown'/white wire into the alternator ground causing the short. Fixit-P has a very good alternator schematic that shows the circuit in the alternator that shows the diodes.

Now that we now where the bear s--t in the buckwheat we can get down to the real stuff.
You have been given some real bad advice by the tech rep. Considering the electrical load on your system a one wire alternator is the last thing you want to do. Now you won't need the resistance wire or the sensor wire for the alternator but you'll be wondering why your alternator won't keep up with the current draw and why your lights flicker and a host of other weird things.If you have not already done so do not buy a one-wire alternator. Either get a new SI or better yet get a cs 144. They are very easy to wire into the circuit and they fit just like the SI.

http://www.madelectrical.com/electri...hreewire.shtml

See this.---http://temp.corvetteforum.net/c3/zman//Electronics/Alternator01.htm

Replacing the resistance wire is a piece of cake and all it involves is to restring a length of normal brown wire to replace the resistance wire and then wire in a 75 ohm 5 watt resistor. If you replace the resistance wire you will have to do this anyway. This will allow you to keep the charging light if you had one.

The second thing to do would be to wire a sensing wire to terminal 2 on the SI alternator or to the S terminal on the CS alternator. The resistor wire goes to the no.1 terminal on the SI alternator and to the L terminal on the CS alternator. Are you still with me?---http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml

As to you question on the junction block. From what I'm reading you are fine with that, as long as the main hot feed to it from the battery is a heavy enough wire. Your ignition hot wire should be fine if you are only using it to power the relays. A wiring diagram would help but I can picture most of it.

Now some more meat.
Your alternator needs to read the current draw AKA voltage drop downstream away from the battery and away from the back of the alternator output post. The alternator output wire would be real happy if it was run to the input of the junction block and tied into the hot feed wire from the battery. The red sensor wire would be pretty pleased to be tied there also.
Don't for get the rest of the harness for the truck feeds such as the horn lights radio et.al. This would be the red wire that goes from the junction on the right fender to the firewall block.
You think about this stuff and re-read the thread and come back with the questions.
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Old 04-22-2011, 10:57 PM   #10
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

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Originally Posted by VetteVet View Post
Well darn.
I saw your post this morning about the wire smoking again and I was going to respond and I had to leave and go to the store.
I see just now that you talked to the tech rep at AAW and he told you the exact same thing I was going to tell you. If you read Fixit-P s post he asked for more information and that is what we really needed from the start. Now that we know what type alternator you have we have a course to follow to help.

The wire that has been smoking is the old resistance wire for the stock 7 gauge truck dash and I posted the diagram above. It is the 3rd one in that post.
I figured you had shorted a diode in the SI alternator and it was pulling too much current through the brown'/white wire into the alternator ground causing the short. Fixit-P has a very good alternator schematic that shows the circuit in the alternator that shows the diodes.

Now that we now where the bear s--t in the buckwheat we can get down to the real stuff.
You have been given some real bad advice by the tech rep. Considering the electrical load on your system a one wire alternator is the last thing you want to do. Now you won't need the resistance wire or the sensor wire for the alternator but you'll be wondering why your alternator won't keep up with the current draw and why your lights flicker and a host of other weird things.If you have not already done so do not buy a one-wire alternator. Either get a new SI or better yet get a cs 144. They are very easy to wire into the circuit and they fit just like the SI.

http://www.madelectrical.com/electri...hreewire.shtml

See this.---http://temp.corvetteforum.net/c3/zman//Electronics/Alternator01.htm

Replacing the resistance wire is a piece of cake and all it involves is to restring a length of normal brown wire to replace the resistance wire and then wire in a 75 ohm 5 watt resistor. If you replace the resistance wire you will have to do this anyway. This will allow you to keep the charging light if you had one.

The second thing to do would be to wire a sensing wire to terminal 2 on the SI alternator or to the S terminal on the CS alternator. The resistor wire goes to the no.1 terminal on the SI alternator and to the L terminal on the CS alternator. Are you still with me?---http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml

As to you question on the junction block. From what I'm reading you are fine with that, as long as the main hot feed to it from the battery is a heavy enough wire. Your ignition hot wire should be fine if you are only using it to power the relays. A wiring diagram would help but I can picture most of it.

Now some more meat.
Your alternator needs to read the current draw AKA voltage drop downstream away from the battery and away from the back of the alternator output post. The alternator output wire would be real happy if it was run to the input of the junction block and tied into the hot feed wire from the battery. The red sensor wire would be pretty pleased to be tied there also.
Don't for get the rest of the harness for the truck feeds such as the horn lights radio et.al. This would be the red wire that goes from the junction on the right fender to the firewall block.
You think about this stuff and re-read the thread and come back with the questions.
I wish I would have waited for your responce I jummped ahead and had My 10Si Alternater converted to a 1wire earlier today My dash has guages not lights. Now Did I go and screw things up by converting my 10Si to a 1wire or can I get away with it now that I did it I guess I wasn't patient enough been working on this for a while weather has been nice i just want to drive it? thanks again
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Old 04-22-2011, 11:48 PM   #11
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Wow I wish I would have know this before hand looks like I will be changing back over to 3wire sooner than I was expecting "And so the result of this ONE-WIRE method would be dimmer lights and overall weak electrical system performance; in fact often worse performance than with the original" from the mad tec articalThis Sucks.
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Old 04-23-2011, 02:25 AM   #12
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

If you had someone convert your three wire to a one wire, all they did was change the internal voltage regulator because that's the only difference. In all honesty if I were you and I had the electrical loads that you do I'd get a CS 144 and sell the one wire to some hot shot who thinks they are the greatest.
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Old 04-23-2011, 02:53 AM   #13
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Quote:
Originally Posted by stich626 View Post
<hyjackie> "resistor" explain please. my truck has been converted to internal reg alt. and the rewire looks "ok" other than the two that you cross at the old reg plug. they just snipped them.
but what is this about a resistor, the alt in it is a basic 63 amp (and 15 volts at idle)
but I have a new 84 t/a ho 96amp waiting..
????????????????
Quote:
Originally Posted by petey-pablo View Post
Wow I wish I would have know this before hand looks like I will be changing back over to 3wire sooner than I was expecting "And so the result of this ONE-WIRE method would be dimmer lights and overall weak electrical system performance; in fact often worse performance than with the original" from the mad tec articalThis Sucks.
Yeah I agree with Vettevet that autowire tech's advice was a cop out the one wire is a downgrade as you have found out. here is the diagram Vette referred to earlier of the SI alt.

The #1 terminal which is the field terminal is also connected to the diode trio which is connected directly to the stator, so that means the diode trio will see and can handle full alternator voltage (the resistor is not there to drop voltage to the field). What the diode trio can not handle is full alternator current (amps) so the resistor in the field wire limits current flow through the diode trio thereby protecting it. The diode trio is rated @ ~3-5 amps and if you were to have a problem with the cab supply wire (maybe high resistance at the bulkhead connector) and you had a high demand in the cab the field wire will try to fill that demand and short out the diode trio but with the resistor it limits what you can draw from the diode trio. By limiting current from the diode trio the resistor also prevents engine run on because once the alternator is excited it is self sufficient. The CS alts don't have a diode trio but the resistor protects the regulator instead. As Vette stated the CS is the better upgrade mainly because they have delta stators and deltas can produce higher amperage at lower rpms. A popular mod in the rice rocket scene is to rewire the bikes Wye stator alternators into deltas because of the higher output. Here is a diagram of the CS alts with the recommended resistor values in the upper left.
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Old 04-23-2011, 04:37 PM   #14
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

VetteVet, in your earlier post you are showing the 10 DN (Ext Reg) alternator with the resistor going to the Acc post, but on the 10SI (In Reg) you are not. I think that may add to the confusion. You did say, "the diagram with the idiot light and the Accessory wire feed to the fuse panel is left out but it still is in the circuit". I assume this qualifying statement is to let people know that the original resistor is still in the circuit, but by omission it makes it vague and confusing.
I like this drawing a little better because it helps to shows that nothing under the dash needs to be changed when converting from the DN to the SI alternators.

Fixit-p, I changed your drawing a little. Voltage on terminal #1, is connected to one side of the field, but it also biases TR1, turning it ON. In order for current to flow through the field, it needs a ground and it is supplied through TR1.

I think we're going to be in some disagreement over the roll of the resistor that is in parallel with the indicator lamp.
That resistor has one primary function. If the lamp fails, the regulator and generator will continue to function normally. If you didn't have the resistor and the lamp went bad, you would have an open circuit. The resistor completes the circuit if the lamp is bad. The resistor allows a different voltage on each side of the lamp so that the lamp will glow when there is a generator failure.

I don't know if the "resistor limits current flow to from the alt protecting the regulator or diode trio" as fixit-p said. It INCREASES current flow to the regulator.
You know,,, two resistors in parallel (resistor and lamp) have less resistance than either, alone.

If you use the lamp and no resistor the Alt will not begin to charge, but the lamp will glow. The voltage at terminal #1 will be too low for the field and TR1 will not be turned ON. The Alt has some residual magnetism. so you must rev the motor high enough so that the diode trio can provide the current necessaryfor the Alt to begin to charge.

If you are wiring from scratch or don't have an Acc, ignition post such as an older truck with DC generator you can wire a resistor directly across the lamp.
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Old 04-24-2011, 01:13 AM   #15
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Quote:
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Fixit-p, I changed your drawing a little. Voltage on terminal #1, is connected to one side of the field, but it also biases TR1, turning it ON. In order for current to flow through the field, it needs a ground and it is supplied through TR1.
No problem, that was a diagram I used in a earlier thread where I was just trying to illustrate that the diode trio is connected to the stator and not the rectifier bridge making the alt self sustaining, your edit does show the complete path to ground.

Quote:
Originally Posted by RichardJ View Post
I think we're going to be in some disagreement over the roll of the resistor that is in parallel with the indicator lamp.
That resistor has one primary function. If the lamp fails, the regulator and generator will continue to function normally. If you didn't have the resistor and the lamp went bad, you would have an open circuit. The resistor completes the circuit if the lamp is bad.
It has always be my position that the resistor adds redundancy to the system in case of a bulb failure, so no disagreement there. The system will work with both in parallel or either just the bulb or resistor.

Quote:
Originally Posted by RichardJ View Post
I don't know if the "resistor limits current flow to from the alt protecting the regulator or diode trio" as fixit-p said. It INCREASES current flow to the regulator.
You know,,, two resistors in parallel (resistor and lamp) have less resistance than either, alone.
Resistance limits current flow.
and from what I gathered from the OP is that he has a 7 gauge cluster so I wasn't referring or implying that resistors in parallel values are additive as in if they were in series. To calculate resistor value when wired in parallel the following formula applies. I know you know this RichardJ this is intended for others who may read this.


Quote:
Originally Posted by RichardJ View Post
If you use the lamp and no resistor the Alt will not begin to charge, but the lamp will glow.
This I disagree with, the system will work fine with just the lamp. Here is the original diagram as published by Delco with just the lamp.
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Old 04-24-2011, 02:55 AM   #16
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

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Originally Posted by RichardJ View Post
VetteVet, in your earlier post you are showing the 10 DN (Ext Reg) alternator with the resistor going to the Acc post, but on the 10SI (In Reg) you are not. I think that may add to the confusion. You did say, "the diagram with the idiot light and the Accessory wire feed to the fuse panel is left out but it still is in the circuit". I assume this qualifying statement is to let people know that the original resistor is still in the circuit, but by omission it makes it vague and confusing.

I had a problem of not knowing what I was dealing with because Petey did not say what type of alternator he was using and what electrical draw he had so I was trying to cover all the bases.Once I got the details it narrowed down the problem considerably.

I was afraid that this might be confusing because it does not show the parallel resistor. That's why I added the text. The second diagram I posted shows the routing to the firewall block but does not show the brown wire going all the way back to the gauge cluster plug. I was hoping I wouldn't have to write a term paper to illustrate the circuit.The red arrows show the brown wire to the idiot light that parallels the resistor wire, Brown/White. The feed wire for the idiot light comes from the Key switch to the dash cluster via the fuse panel, to complete the parallel circuit back to the firewall plug, and from there it is one brown wire to terminal 4 on the external voltage regulator OR to terminal 1 on the I/R alternator.

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I like this drawing a little better because it helps to shows that nothing under the dash needs to be changed when converting from the DN to the SI alternators.

Fixit-p, I changed your drawing a little. Voltage on terminal #1, is connected to one side of the field, but it also biases TR1, turning it ON. In order for current to flow through the field, it needs a ground and it is supplied through TR1.

I think we're going to be in some disagreement over the roll of the resistor that is in parallel with the indicator lamp.
That resistor has one primary function. If the lamp fails, the regulator and generator will continue to function normally. If you didn't have the resistor and the lamp went bad, you would have an open circuit. The resistor completes the circuit if the lamp is bad. The resistor allows a different voltage on each side of the lamp so that the lamp will glow when there is a generator failure.

In this we disagree. The resistor does provide an alternate path for field excitation, however it also protects the transistors in the internal voltage regulator, and it also prevents feedback from the diode trio to the ignition circuit, which would allow the engine to continue to run with the key off.
The resistor has nothing to do with the light function as it is controlled by the voltage potential of the battery and the voltage output of the alternator. The resistance of the light itself determines the intensity of the light in concert with the voltages of the battery and the alternator.


I don't know if the "resistor limits current flow to from the alt protecting the regulator or diode trio" as fixit-p said. It INCREASES current flow to the regulator. I don't thin so.
You know,,, two resistors in parallel (resistor and lamp) have less resistance than either, alone.

If you use the lamp and no resistor the Alt will not begin to charge, but the lamp will glow. The voltage at terminal #1 will be too low for the field and TR1 will not be turned ON. The Alt has some residual magnetism. so you must rev the motor high enough so that the diode trio can provide the current necessary for the Alt to begin to charge.

Again I disagree, what you describe is a one-wire where-in the field is excited by the residual magnetism
in the field and aided by leak over current from the one-wire regulator. With the light you get instant voltage and current to the alternator field and full voltage at idle.


If you are wiring from scratch or don't have an Acc, ignition post such as an older truck with DC generator you can wire a resistor directly across the lamp.
I have a 1967 and you are correct. I think both my brown wire and the resistor wire are on the same key switch terminal and The brown wire goes to the cluster plug and to the idiot light and then to the firewall plug. I still have both the light and the resistor wire in parallel.

I appreciate your input.
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Old 04-25-2011, 03:24 AM   #17
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

I am all confused now haha.. anyway I have two wires on my ignition switch that are both crimmped together a larger gauge Brown wire and the smaller gauge brown white striped wire in question they both goback to the Fuse block & into the engine bay wiring I don't think anyone of the two go back up to the gauge cluster.. With This All Said I am convinced to switch over to a CS 144 IF IT FITS On MY Same Pully Setup if Not I will buy a new 10Si 3wire
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Old 04-25-2011, 08:32 AM   #18
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

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Originally Posted by VetteVet View Post
The brown/white wire you describe runs from the key switch to the firewall block on the diagrams I have. It is joined there by a solid brown wire that runs back to the cluster plug to pin 8 on the idiot light dash. It is used to feed the alternator field exciting circuit through the regulator.The ammeter dash does not have this wire. On the other side of the firewall block (engine side) it goes to solid brown and goes to the terminal 4 on the external regulator and if the alternator has been converted to internal regulator it runs to terminal 1 on the alternator.

This diagram shows the b/w wire from the key switch.

Attachment 736112

This one shows it continues to the firewall block, joining with the other brown wire to the cluster plug.

Attachment 736114

Here is the alternate view of the brown wire going from the key switch to the external voltage regulator.
Attachment 736111


Here is the conversion diagram. It shows the diagram with the idiot light and the Accessory wire feed to the fuse panel is left out but it still is in the circuit.

Attachment 736110

Now if some one has converter the alternator and ran a separate wire maybe they just cut the stock wire off and left it hanging and it may be touching a ground. This wire is hot from the key and is not fused except by the fusible link near the battery. It is small enough to burn before the FL in any case and the burn would start nearest the hot source and continue to the ground.

If you were using this wire to feed the high amp fans without a relay then the amperage draw would be enough to burn the insulation off the wire. You are right to trace the wire from the key switch to wherever it goes. If you replaced it where did you run it to?
This was from my first reply. Not knowing what system you have I tried to cover both and was not very effective. Also I was unsure of how much wiring you were missing. The good thing is that as we go along in these threads,we get to the answers in most cases. When I reply I try to speak to the other readers as well as to the original poster.
Sometimes we get caught up in technospeak and lose the main purpose of the forum which is to help the guy with with the problem.

Anyhow I think you are making a wise decision.
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Old 04-25-2011, 01:13 PM   #19
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

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Originally Posted by petey-pablo View Post
CS 144 IF IT FITS On MY Same Pully Setup if Not I will buy a new 10Si 3wire [/B]
I think you should be okay, but remember if size is an issue the CS144 has a 144 mm case diameter and the CS130 has a 130mm diameter case. If you go with the SI series alt I would recommend the 12 over the 10 because it has a better design for cooling.
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Old 04-25-2011, 03:03 PM   #20
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Last first?
If you change your mind again and get a CS, be sure and note that the CS130 is not the same as the CS130D. The CS130 has one external fan and one internal fan. The CS130D/CS144 have two internal fans and none on the outside.
CS 130

If heat was the criteria, you should stick with the DN. Runs a lot cooler because there is less junk inside to block the air flow. That's just my opinion. My '67 has Climate Control AC, small CD radio, HEI, 2 electric fans and electric trailer brake running off the original 10DN Alt so what do I know?

I've seen a few bad alternators, but I have never seen one that burned the wires under the dash. I really don't think the Alt caused the problem.
You have a wiring harness for idiot lights and a dash with gauges. In VetteVet's first and recent diagrm, you can see that there is a different pin-out for the gauge dash.

I think the problem could be in the harness, but more likely in the missmatch in the dash pin-out.
Is your American Autowire harness similar to the OEM harness as far as the fuse block and bulkhead connector are concerned? You do understand that they are two separate items and can be separated by releasing some clips?

That last brown wire you ask about, at the ignition switch, goes into the back of the fuse panel. it supplies power to fuses for the wiper motor, htr blower, back-up lights and instrument cluster. Any problem with any of those working?
Of more concern is what is on the other end of the brown/white strip wire. On VetteVet's first post, he mentioned that the brown/white wire is connected to a brown wire at the pin on the back of the bulkhead connector and that this brown wire goes to the idiot light dash connector.

You need to separate the fuse panel from the bulkhead connector and find that brown wire. Follow that brown wire into your gauge dash and see what it really connects to. Going to a heater lamp should not have cause a problem.

What works? What gauges or lights of any kind do not work?
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Old 04-26-2011, 01:14 PM   #21
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

In the images below you can see the wires in question The brown white wire I followed through the firewal fuseblock it goes to the Alternator The Brown wire goes to the fuses I marked in the picture in the fuse block. and the other picture is of my burnt wire..None of the two wires go to the gauge cluster..


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Old 04-26-2011, 02:07 PM   #22
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Re: BROWN WHITE Striped wire from the Ignition switch Burnt what can cause this?

Those 2 wires are both hot in the run position and I believe cold in the start position, the solid brown is as Richard stated "supplies power to fuses for the wiper motor, htr blower, back-up lights and instrument cluster". The brown with white stripe is the alt field wire and according to the diagram if it were wired in parallel with the idiot light the brown wire that would go to the cluster would be tapped at the bulkhead connector, (just an fyi, I did the math if a 10 ohm resistor were wired parallel with a 194 bulb the resistance would be ~8.4ohms). If it were me I would get rid of that resistor wire and install a new stranded copper 18 or 20 awg wire with a 10 ohm, 6 watt resistor soldered and shrink wrapped. That way even if you were to have a dead short the resistor is going to convert ~19 watts of energy in a very localized area whereas the resistor wire dissipated all that energy along its entire length which you could see is a fire hazard. Imho heat should always be considered, if it wasn't important these alternators wouldn't have fans on them.
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