Alternator Internal regulator convertion

[berencam]

When i purchased the 70 i have, it was already 'converted' to an internally regulated alternator. It however is not charging my battery. So i need to know where the two wires that come out of the alternators molded connection go, and where the wire that hooks up to the stud on the back of the alternator goes. If i need to give more information just ask.

[VetteVet]

Originally Posted by berencam

When i purchased the 70 i have, it was already 'converted' to an internally regulated alternator. It however is not charging my battery. So i need to know where the two wires that come out of the alternators molded connection go, and where the wire that hooks up to the stud on the back of the alternator goes. If i need to give more information just ask.

I quoted you so I could answer your questions better.
How do you know that the alt is not charging? Have you measured the output with a voltmeter at the positive and negative battery terminals? You may have a bad battery.

The large red wire goes to a threeway connection with two other wires one of which goes back to the battery. In conversions this wire can be run to the battery directly or to the large terminal on the solenoid.

The small terminals on top of the alternator are used to charge the fields in the alternator and to turn on the regulator inside the alternator and tell it what amperage to charge. If you have the alternator mounted on the drivers side of the engine then the terminal next to the engine is the field wire. This wire needs to be connected to any 12 volt source from the battery. It can be hot or keyed hot. Some guys just run a jumper from the post on the back of the alternator to this terminal. See----- http://67-72chevytrucks.com/vboard/s...d.php?t=119379 It is better to wire it from the fuse panel for a more accurate voltage sensing of the electrical system, but it will still work.

The other wire is the sensing wire from the old external regulator, which was a blue wire, which was an extension of the brown wire to the regulator which came from the charging light in the dash, or from the ignition switch if you have an ammeter in the dash. If you have the seven gauge dash with the ammeter then you will need to install a resister in the brown wire before it hooks to the alternator. The alternator needs to see this resistance to avoid blowing the internal diodes in the regulator. If you have the idiot light then the light filament supplies the resistance.Below is a diagram of the original wiring showing the red wire connections and the blue,brown and white wires on the external regulator.

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[berencam]

Originally Posted by VetteVet

I quoted you so I could answer your questions better.
How do you know that the alt is not charging? Have you measured the output with a voltmeter at the positive and negative battery terminals? You may have a bad battery.

The large red wire goes to a threeway connection with two other wires one of which goes back to the battery. In conversions this wire can be run to the battery directly or to the large terminal on the solenoid.

The small terminals on top of the alternator are used to charge the fields in the alternator and to turn on the regulator inside the alternator and tell it what amperage to charge. If you have the alternator mounted on the drivers side of the engine then the terminal next to the engine is the field wire. This wire needs to be connected to any 12 volt source from the battery. It can be hot or keyed hot. Some guys just run a jumper from the post on the back of the alternator to this terminal. See----- http://67-72chevytrucks.com/vboard/s...d.php?t=119379 It is better to wire it from the fuse panel for a more accurate voltage sensing of the electrical system, but it will still work.

The other wire is the sensing wire from the old external regulator, which was a blue wire, which was an extension of the brown wire to the regulator which came from the charging light in the dash, or from the ignition switch if you have an ammeter in the dash. If you have the seven gauge dash with the ammeter then you will need to install a resister in the brown wire before it hooks to the alternator. The alternator needs to see this resistance to avoid blowing the internal diodes in the regulator. If you have the idiot light then the light filament supplies the resistance.Below is a diagram of the original wiring showing the red wire connections and the blue,brown and white wires on the external regulator.

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thats exactly what i need, i am getting 13.4v at the battery when the engine is running. also if i remove the pos cable from the battery when i am running the truck shuts off. It is wired as you have explained with the exception of the last wire. it does go into the cab, but then i loose it. I have an after market gauge inside it. So basically that last wire needs to go from ignition fused to ammeter, from ammeter to a resistor, from resistor to alternator? What resistor?

[berencam]

ttt i just need to know how to wire that last wire exactly without using factory harnesses, found out the alt was dead.

[slikside]

subd.

[slikside]

So I plan to do this conversion. I have a '72 C-10 350, same as the truck in the thread to which VettVet refers above. I'm just going to a 10SI, 63 amp which I already have. I have the 7 gauge cluster with the ammeter gauge...no idiot light.

VettVet says for this situation that a resistor needs to be installed in the brown (into blue) wire before connecting to the alternator.

Question is, what type/rating of resistor should I put there? Is that just a RadioShack thing, or where else would you find such a resistor?

Also, I believe the "how to" thread above is showing a 12SI, but I'm thinking that all the terminals on the alt, and associated wiring guidance above is all the same for my 10SI, correct??

Thanks.

[CastIron]

I switched to 10SI alternators the same way on both my 72 chevelle with an idiot light and my 69 c1500 with an ammeter.
What I did: unplug the external regulator connector and splice the brown and blue wires together. (the two wires on the outside ends of the connector) Then install the new alternator and remove the terminals from the original alternator plug. Using a newer style plug, install the original blue wire into the #1 position and run a wire from #2 position to the battery stud along with the original battery wire. You'll have an extra wire, just tape that in the original harness.
I did this years ago on both and have never had any problem with either. They both put out about 60A compared to the 30A from the original 10DN alternators. I hope this helps!

[kwmech]

Why does everybody insist on not pulling the harness apart. If you peel the tape back you will see that the blue and white wires are exclusive to the external regulator. I've always just eliminated the wires and extended the brown wire to the alt and retape the harness. The extra red wire gets eliminated also. New regulator gets looped from the bat post. Been working for me for the last 30+ years.

[VetteVet]

Originally Posted by slikside

So I plan to do this conversion. I have a '72 C-10 350, same as the truck in the thread to which VettVet refers above. I'm just going to a 10SI, 63 amp which I already have. I have the 7 gauge cluster with the ammeter gauge...no idiot light.

VettVet says for this situation that a resistor needs to be installed in the brown (into blue) wire before connecting to the alternator.

If you have the seven gauge dash then You already have a resistance wire from the key switch to the cab side of the firewall harness plug. I don't think I knew that for sure back in 2009 so I had to add the need for the resistor. The charging light supplies the 10 ohms resistance needed for the 10 SI alternators. It runs to the same place on the cab side of the firewall plug.


Question is, what type/rating of resistor should I put there? Is that just a Radio Shack thing, or where else would you find such a resistor?

If you convert to the CS alternator which is better than the SI you will need to install resistor in the brown wire. This can be anywhere from a 35 0hm 1 watt to a 300 ohm .5 watt resistor and they are available from radio shack.


Also, I believe the "how to" thread above is showing a 12SI, but I'm thinking that all the terminals on the alt, and associated wiring guidance above is all the same for my 10SI, correct??

You are correct the SI,s are wired the same.

Thanks.

Originally Posted by kwmech

Why does everybody insist on not pulling the harness apart. If you peel the tape back you will see that the blue and white wires are exclusive to the external regulator. I've always just eliminated the wires and extended the brown wire to the alt and retape the harness. The extra red wire gets eliminated also. New regulator gets looped from the bat post. Been working for me for the last 30+ years.

I think it's mainly for convenience or possibly if they just want to go back to original someday. If you have followed my posts on the conversion, I usually recommend just what you said. With the exception that I don't recommend looping the number 2 terminal back to the output terminal on the alternator.
Here's why.

When you do that you eliminate the ability of the internal regulator to sense the voltage drop on the electrical system downstream of the alternator. This means that the alternator regulator senses, just the output voltage of the alternator, and doesn't compensate for the drops in voltage from the loads in the electrical circuits in the truck. It can result in less voltage going to the wipers, heater, headlights etc. especially at idle. In a stock truck it may not be too noticeable, but if you have electric cooling fans or other high draws it will.

In the FAQ conversion by Toddtheodd, he says to jump the brown wire to the blue wire and and run it to the no.1 terminal on the alternator and loop the no. 2 terminal over to the output post on the alternator. In actuality the white wire should be jumped with the brown wire and the blue wire gets jumped to the red wire in the plug and run to the no. 2 terminal because it is the sensing wire for the stock harness. Then you just have to change the small plug on the harness to fit the SI alternator. You can still remove the external voltage regulator and the regulator plug.

Here is a picture of how I do it. I run the brown wire straight to the alternator and then I extend the red wire from the EVR plug to the no.2 terminal on the alternator. You get rid of the EVR harness and keep the remote voltage drop sensing for the alternator .







If you notice the other wires in the diagram, the black wire and the black/white wire, these are the feed wires for the ammeter (battery gauge) in the seven gauge dash panel. They are connected to the ends of the red wire in the left of the diagram, along with the battery on one end and the alternator output wire on the other end. The red wire is called a SHUNT, which means it shunts power between the battery and the alternator output. If you run the alternator output wire straight to the battery positive terminal like a lot of guys do especially with a one-wire alternator, then the ammeter will not read or it will not read correctly. In the 74 year, I think, GM converted to the voltmeter and ran the alternator output wire to the large post on the starter solenoid.

Also if the battery gauge is not working it's usually the fault of one of those 4 amp fuses shown in the diagram.

Here's another favorite diagram of mine showing the SHUNT and the ammeter wires.

[slikside]

VettVet,

Thanks for chiming in again here. I follow you right up until you mention the charging light providing the needed resistance. I only have 2 lights in my cluster, both are in the bottom of the fuel gauge: BRAKE and TEMP. I have no Charging light, or Elect, or ALT light. Does my brown wire still have the needed resistance or would I need to add a resistor??

I noticed one of the posters above, as well as in the FAQ thread, that neither of them mentioned adding a resistor.

Not trying to be redundant, but electrical is not really my thing (I'm learning). I just don't want to inadvertently fry something doing this conversion.

Thanks a bunch.

Steve

"If you have the seven gauge dash then You already have a resistance wire from the key switch to the cab side of the firewall harness plug. I don't think I knew that for sure back in 2009 so I had to add the need for the resistor. The charging light supplies the 10 ohms resistance needed for the 10 SI alternators. It runs to the same place on the cab side of the firewall plug."

[slikside]

Originally Posted by CastIron

I switched to 10SI alternators the same way on both my 72 chevelle with an idiot light and my 69 c1500 with an ammeter.
What I did: unplug the external regulator connector and splice the brown and blue wires together. (the two wires on the outside ends of the connector) Then install the new alternator and remove the terminals from the original alternator plug. Using a newer style plug, install the original blue wire into the #1 position and run a wire from #2 position to the battery stud along with the original battery wire. You'll have an extra wire, just tape that in the original harness.
I did this years ago on both and have never had any problem with either. They both put out about 60A compared to the 30A from the original 10DN alternators. I hope this helps!

Yes, it does help. I like your idea of removing the terminals from the original plug, and inserting the blue into the new style plug.

And it doesn't sound as though you've had any issues on your GMC doing it the way you said WITHOUT a resistor installed in the brown wire.

Thanks for posting.

EDIT: By the way, how do you remove those wire terminals from their plugs?

[RichardJ]

The first drawing below with the external regulator is very little different than the drawing for the 10SI internal regulated alternator. All they did was stuff the regulator and a couple pieces of wire inside the alternator case.

The exciter wire from the voltage regulator, whether the regulator is on the radiator support or inside the Alt, goes to the idiot lamp and to the ignition switch. That wire going to the ignition switch is actually a resistor wire, not a free-standing resistor component. That resistance wire is in the harness, whether it has a idiot light or an Ammeter gauge.

Unless the harness has been altered, you do not need to add a resistor. It's already there.

VetteVet was talking about adding a different resistor if you were going to install a CS alternator.

The wire on the engine side of the firewall that goes to the regulator is a standard copper wire.

[VetteVet]

Thanks Richard for the clarification. It can be confusing when I try to explain both systems.

[slikside]

Originally Posted by RichardJ

The first drawing below with the external regulator is very little different than the drawing for the 10SI internal regulated alternator. All they did was stuff the regulator and a couple pieces of wire inside the alternator case.

The exciter wire from the voltage regulator, whether the regulator is on the radiator support or inside the Alt, goes to the idiot lamp and to the ignition switch. That wire going to the ignition switch is actually a resistor wire, not a free-standing resistor component. That resistance wire is in the harness, whether it has a idiot light or an Ammeter gauge.

Unless the harness has been altered, you do not need to add a resistor. It's already there.

VetteVet was talking about adding a different resistor if you were going to install a CS alternator.

The wire on the engine side of the firewall that goes to the regulator is a standard copper wire.

Originally Posted by VetteVet

Thanks Richard for the clarification. It can be confusing when I try to explain both systems.

Ahhh, I got it now. The brown wire itself is the resistor for my application. I needed to make sure I was understanding exactly what was being said, and not just hearing what I wanted to hear (no resistor).

In this case it looks like they're one in the same. Merry Christmas to me!!

Thanks every one for the responses. It'll be after Christmas before I do this, but I'll let you know how it goes.

Steve

[RichardJ]

>>Ahhh, I got it now. The brown wire itself is the resistor for my application.<<

NO, NO, NO.

The brown wire in VetteVet's image is just a copper wire. The under dash harness on the inside of the firewall, that the brown wire connects to is where you will find the resistance wire. BUT, as I said in my other post;
>>goes to the idiot lamp and to the ignition switch. That wire going to the ignition switch is actually a resistor wire, not a free-standing resistor component. That resistance wire is in the harness, whether it has a idiot light or an Ammeter gauge.<<

>>The wire on the engine side of the firewall that goes to the regulator is a standard copper wire.<<

[slikside]

OK. Maybe I've got it this time: The brown wire is NOT the resistance wire, but the voltage it carries has been "resisted" due to it's connection to the resistance wire in the harness.

[BLT gmc]

sub'd

[slikside]

[QUOTE=VetteVet;6966425][B][COLOR="Red"]I think it's mainly for convenience or possibly if they just want to go back to original someday.


In the FAQ conversion by Toddtheodd, he says to jump the brown wire to the blue wire and and run it to the no.1 terminal on the alternator and loop the no. 2 terminal over to the output post on the alternator. In actuality the white wire should be jumped with the brown wire and the blue wire gets jumped to the red wire in the plug and run to the no. 2 terminal because it is the sensing wire for the stock harness. Then you just have to change the small plug on the harness to fit the SI alternator. You can still remove the external voltage regulator and the regulator plug.

Just did this today. I wanted to keep all the original wiring, and preserve the option to go back to that set up, if I or anyone else ever wanted to. I didn't need to cut a single wire. I made jumpers with male spades on both ends to facilitate the connection using the 4 wire EVR plug itself (another idea I got from some thread on these boards). I jumped the wires just as VettVet says above, and used the original blue and white wires to the alternator terminals also as above using the appropriate new alternator plug.

Everything appears to work great. The ammeter works just as it did before the upgrade.

I can't get over the wealth of information available on this site. Many thanks to those with knowledge who share it so willingly. I'm amazed at how simple this was to do, yet would have never been able to do it without all the guidance found here.

Thanks again!

Here's what mine looks like:

[davepl]

Glad it's working! I did mine just like yours in the photo (though I kept the stock color wiring at the alternator, even though the plug is clearly different to anyone who knows).

I did mine like this because I have the dual battery option and the regulator is well hidden. When I did it on my other cars where it's exposed, I gutted the regulator and did the jumpers inside so it -looks- like the regulator is there, but inside it's just doing what your red and white jumpers are doing.

Does anyone know what effect, if any, this has on the little capacitor thing next to the regulator? I've always assumed it was just there to "dampen" the electrical pulses when the regulator opened or closed, and that without the external regulator it's not needed, but I do not actually know.

In other external regulator news, 20 years ago I had a problem of the battery boiling on long trips, never on short trips, yet everything checked out and the voltages were fine. Turned out to be one of those old "click style" Carter fuel pumps. It puts a high, but very brief, load on the charging system. This caused the regulator to kick into 'charge' but it can only kick back out so fast (mechanical relay). If the pump load is shorter than the regulator reaction time, once the battery is full this extra charging adds up over a number of hours and will cook the battery. That's the second hardest thing I think I've had to chase down.

[VetteVet]

Originally Posted by davepl

Glad it's working! I did mine just like yours in the photo (though I kept the stock color wiring at the alternator, even though the plug is clearly different to anyone who knows).

I did mine like this because I have the dual battery option and the regulator is well hidden. When I did it on my other cars where it's exposed, I gutted the regulator and did the jumpers inside so it -looks- like the regulator is there, but inside it's just doing what your red and white jumpers are doing.

Does anyone know what effect, if any, this has on the little capacitor thing next to the regulator? I've always assumed it was just there to "dampen" the electrical pulses when the regulator opened or closed, and that without the external regulator it's not needed, but I do not actually know.

In other external regulator news, 20 years ago I had a problem of the battery boiling on long trips, never on short trips, yet everything checked out and the voltages were fine. Turned out to be one of those old "click style" Carter fuel pumps. It puts a high, but very brief, load on the charging system. This caused the regulator to kick into 'charge' but it can only kick back out so fast (mechanical relay). If the pump load is shorter than the regulator reaction time, once the battery is full this extra charging adds up over a number of hours and will cook the battery. That's the second hardest thing I think I've had to chase down.

This is valuable information and another good reason to convert to internal.
makes me wonder what effect the AC clutch kicking in and out has. Since it is much slower than the fuel pump it may not be a factor.

[RichardJ]

The condenser on the voltage regulator is for noise suppression for the radio. Without that condenser you would hear buzzing in the radio from the regulator relay contacts opening and closing. The same goes for the condenser bolted to the side of the ignition coil and wired with the 12volt wire on the + post.
Vehicles with radio delete would not normally have those two condensers installed at the factory.

Original factory external voltage regulators were mechanical with one or two relays inside.
If you look for a replacement voltage regulator, you will find an original mechanical regulator for $50-$60, that may even say Delco on it.
If you find one for about $20, weighs 1/3 the original and doesn't have any resistors on the bottom, it is a solid-state unit with semi-conductors just like the voltage regulator inside the internally regulated 10SI alternator.
Some of those regulators have a very short cover on them, buy not all and look just like the mechanical regulators.
The solid-state regulators don't have the voltage spikes (noise) caused by the relay contacts.

[blklblsk8tr13]

Do I have the necessary wires to correctly connect the field wire to a dummy light setup?

I connected the field wire to the small brown wire that went to the external regulator, and the dummy light comes on but the alt. never begins to charge., and the dummy light stays on.

lots of wires don't make it out the back of the fuse block due to previous owner being a genius.

all help appreciated,
eric

[VetteVet]

Originally Posted by blklblsk8tr13

Do I have the necessary wires to correctly connect the field wire to a dummy light setup?

I connected the field wire to the small brown wire that went to the external regulator, and the dummy light comes on but the alt. never begins to charge., and the dummy light stays on.

lots of wires don't make it out the back of the fuse block due to previous owner being a genius.

all help appreciated,
eric

I would like to work with you on this in the electrical section since it's an old thread. However if you can check the voltage on the brown wire with the key off and then with the key on looking for zero volts key off and 12 volts key on, you should only need to add a hot all the time wire to the no. 2 terminal and the alternator light should work as designed.

This is providing that the alternator is the SI internal regulated type, and not the old external regulated style. You can even loop a short wire from 2 over to the large output terminal on the back of the alternator.

If your alternator is the one-wire type then the charging light will not work. VV

[blklblsk8tr13]

this is the alt I have. so I should put the white wire to the brown wire coming from the fuse block?

[VetteVet]

Look at the picture in post 18 and compare the alternator with yours and be sure that the terminals look like this, --- --- and not this I I on your alternator. Some of the later external regulated alternators were similar to the newer style internal regulated ones. Their bodies looked similar but the plug-in terminals are like the old stock style alternators.

The fuse block you refer to is actually the firewall block connector and the brown wire comes from it and runs to the old external voltage regulator. This is all detailed in the posts above. Go back and read them carefully and get familiar with the wiring and you'll be able to wire yours up to work. Since you have not got all the wiring you would have with the original system, you will need to run new wiring to the alternator.

The detailed pictures above show the path of the wiring from the key switch to the stock regulator and alternator, and then how to convert the stock regulator and alternator over to the new internal alternator.
If you check the voltage on the brown wire like I explained and you get the readings. Then run that wire to the alternator to the no. 1 terminal on the alternator. If that's where the white wire goes now, then you can splice the brown wire into it and then connect the no. 2 terminal (red) to a full time hot source and you should be charging.