help with wiring question

[BigBlock67]

Anybody know where the brown wire from the voltage regulater goes? I'm switching to a single wire alternator and want to clean up the wiring. I think it may be the light on the dash.

[stsalvage]

Most of the time the volt metal is unhooked more fires are started in the dash area cus of them wires

[Benjamin]

Yes. I highly recommend bypassing the voltage regulator, but also, hookup all the wires at the alternator, do not run it as a 1-wire. This allows you to retain voltage sensing for the alternator and functioning dash light.

Instead of going into it here, check out my thread, starting on page 2, post #29.

http://67-72chevytrucks.com/vboard/s...=575923&page=2

In my thread I have links to other threads on the forum that were very helpful during my install.

I'm no expert, but the truck has been running strong for the last 6 months, including 3 road trips upwards of 500 miles each.

Good Luck!

[Benjamin]

Benjamin's thread

[VetteVet]

Originally Posted by BigBlock67

Anybody know where the brown wire from the voltage regulater goes? I'm switching to a single wire alternator and want to clean up the wiring. I think it may be the light on the dash.

You are correct about the brown wire but it also joins a resistance wire that runs to the key switch to provide the 10 ohms the alternator needs to excite it in case the light bulb blows. When the factory used the gauge dash they discontinued the light but kept the resistance wire. Instead of the light they included the battery gauge. I have posted on this many times in the electrical board, including how to do the internally regulated alternator conversion.

Here is the diagram I recommend to do the conversion and to replace the external regulator harness and clean up the wiring.




All it does basically is to extend the brown wire from the old regulator plug to the no.1 terminal on the SI alternator, and the red wire from the old regulator plug to the no.2 terminal on the new alternator. The output wire 12 gauge can still be used if you don't plan to use a lot of current draws, but if you do you should go to an 8 gauge and run it to the same junction as the 12 gauge was connected to. If you run it to the battery terminal or the fender junction your battery gauge will probably not work. You can wire a one wire alternator to keep the battery gauge working but the charging light will not work with a one-wire alternator. It will just glow a bright red anytime the key is on.

Our friend STsalvage is confusing the old style amp meter with the newer battery gauge. All the current in the electrical system ran through the old style meter but the newer style only uses a small amount and it has a 4 amp fuse in each of the two wires that carry voltage to it.


Here's a thread with tons of information on the conversion also using the newer CS style alternator.

http://67-72chevytrucks.com/vboard/s...d.php?t=763180

[BigBlock67]

thanks for the help. I'll check out the link you posted.

[Rick Bollinger]

This is great! On my 68 the PO changed to a one wire alternator but just added a spliced in wire to the harness. Well it charges ok but the original alternator harness was just shoved up by the voltage regulator. Nothing taped or deleted just bare wires and connector. Now I know what I need to do to clean up the mess and to delete the voltage regulator. Will wiring in the brown wire to the alt make my stock amp gauge work?

Thanks for the great thread

Rick

[VetteVet]

Originally Posted by Rick Bollinger

This is great! On my 68 the PO changed to a one wire alternator but just added a spliced in wire to the harness. Well it charges ok but the original alternator harness was just shoved up by the voltage regulator. Nothing taped or deleted just bare wires and connector. Now I know what I need to do to clean up the mess and to delete the voltage regulator. Will wiring in the brown wire to the alt make my stock amp gauge work?

Thanks for the great thread

Rick

There are so many guys who install a one wire alternator and then just run the output wire directly to the battery positive. It's just dumb to do that because the alternator is the main power source for the electronics in the truck. A lot of them think the battery provides all the power and the alternator is just there to recharge the battery. While this works on hot rods and tractors, it just doesn't supply all the juice for cooling fans and AC systems and any other high load items.

If you check the diagram in post 5, it shows the correct way to wire the alternator output so that the battery gauge will work and the battery will charge. Notice the small 12 gauge wire from the battery to the main junction.
This is the charging wire for the battery and it also supplies emergency voltage when the alternator fails and when the engine is off.

The alternator output wire runs to the main junction so that it can supply voltage and current to all the systems in the truck. if it's run straight to the battery then all the output from the alternator goes through this small 12 gauge wire from the battery to the main junction. It's too much load for that small wire to carry especially if other loads are added.

The other problem with running the output wire directly to the battery positive is that it defeats the purpose of the battery gauge to measure the output voltage of the alternator and the state of charge of the battery.
Again looking at the diagram, notice the two small wires with fuses. One is connected to the battery at the fender junction and the other is is connected to the main junction with the alternator output wire. They are connected on each end of the smaller 12 gauge battery charge wire. This is so they can sense the voltage on the alternator and the battery and compare the two.
These two wires are both positive and they run directly to the cluster plug in the dash and then directly to the battery gauge.

If you run the alternator output wire to the battery positive they will be right together and the battery gauge cannot tell if the alternator or the battery is working correctly.This is rather simplified but it explains the need to keep the alternator output wire and the battery wire apart. I hope it helps.

The brown wire is just used to excite the alternator and to light the charging light if the charging system fails. if you have a battery gauge then you won't have a charging light anyway. If it's a one wire then the brown wire is not used but the battery gauge will still work if the alternator output wire is wired correctly. the fuses must be good and the wiring must be making contact all the way to the gauge in order for the gauge to work.

[BigBlock67]

Do the fuses in your wiring diagram need to be added or are they already there from the factory?

[Rick Bollinger]

The fuses should be there already. They are in a weird shaped rubber connector holder about 1 1/2 inch long.

[VetteVet]

Originally Posted by Rick Bollinger

The fuses should be there already. They are in a weird shaped rubber connector holder about 1 1/2 inch long.

Looks like this one at the bottom of the pic.

[BigBlock67]

Thanks again. you've been a big help.

[RichardJ]

Those two inline, short, 4Amp fuses are only used if your dash gauges have an Ammeter that is labeled as "Battery". If the fuses are in your engine harness, they probably don't or shouldn't extend past the bulkhead connector.

from your first post,
>> I think it may be the light on the dash.<< You were not clear WHAT you think is the light, but it sounds like you have a Gen warning light.

On the inside of the bulkhead connector, the Brown wire splits into two wires. A brown wire goes to the dash gauge connector and to the Gen light. A second wire is a resistence wire that goes to the ignition Switch. It is shown as Brown/White in the wiring diagrams, but could be a different color.

This Brown wire that used to be connected to #4 on the old Voltage Reg should now be connected to terminal #1 on the new SI Alternator. You should not be making any other changes to this wire. If the gen light worked with the old 10DN alternator it should continue to work with the SI alternator.

[VetteVet]

Originally Posted by RichardJ

Those two inline, short, 4Amp fuses are only used if your dash gauges have an Ammeter that is labeled as "Battery". If the fuses are in your engine harness, they probably don't or shouldn't extend past the bulkhead connector.

from your first post,
>> I think it may be the light on the dash.<< You were not clear WHAT you think is the light, but it sounds like you have a Gen warning light.

On the inside of the bulkhead connector, the Brown wire splits into two wires. A brown wire goes to the dash gauge connector and to the Gen light. A second wire is a resistence wire that goes to the ignition Switch. It is shown as Brown/White in the wiring diagrams, but could be a different color.

This Brown wire that used to be connected to #4 on the old Voltage Reg should now be connected to terminal #1 on the new SI Alternator. You should not be making any other changes to this wire. If the gen light worked with the old 10DN alternator it should continue to work with the SI alternator.

Right on Richard, the confusion may have come from the two posters, the first one has a light and the second one(post 7) has the battery gauge. That's how we got onto the fuses. VV