Quick question Re: Alternator wiring

[Ultrasummer]

I've read most of the posts and haven't seen an answer for this. So I put a new alternator in. Traditional 3 wire type. I went from the original 55 amp to 100 amp with internal voltage regulator. From what I've read at about 100 amps you should consider going with a heavier gauge positive wire. I bought a 6 gauge alternator cable for this. I also bought the handy dandy wiring adapter that is 2 pieces: One is an adapter that plugs into the alternator and connects to old wiring and the Second is a plug that goes in place of the previous voltage regulator. Handy huh? While looking at VetteVet's great illustration of wiring, I am running this new 6 gauge wire to a junction block that will in turn run over to the battery )or junction block near the battery). Now I've got the previous 12 gauge POSITIVE wire coming from the old external voltage regulater that came from the previous attachment to the alternator. What should I do with this 12g old positive wire??? I was just going to go ahead and attach it to the junction block where I have the new 6 gauge wire attached unless you all think it isn't needed.

[maverickmk]

Subscribing as I would like to know as well.

[Andy4639]

The bigger red wire that goes to the back of the alternator and the red wire that went to the external voltage regulator all join together at the drivers side head light area. They are all wrapped in the black rubber tape in the picture. If you ran new wire from battery to alternator you need to make a connection some place to tie them back together.

The smaller red wire from the external can be cut off and not used but I leave enough wire to make a connection later if I need it. You will then jumper the bigger red wire to the number #2 terminal and the brown wire to the #1 terminal.

[Stocker]

Hey Andy, I'm glad you jumped in here. You (and a few others) really saved my bacon a couple years ago when I had similar issues.

[Andy4639]

Originally Posted by Stocker

Hey Andy, I'm glad you jumped in here. You (and a few others) really saved my bacon a couple years ago when I had similar issues.

Thanks you sir, it's nice to hear when you help someone out.

For a stock truck to add the internal regulator it's pretty simple stuff.

Vett has made several post showing the stock wiring and the new wiring for this mod. Most people just jumper the external regulator out and use the old wires. I like how Vett and I do it. Thanks Vett for the diagram pictures.

Cut the connector off at the external volt regulator and the white wire can be took out just clip it off and for get it. Strip the tape back on the harness to where you have enough wire for the brown wire and red wire to make it over to the alternator. Hook them up as in the drawing. The red goes to #2 terminal & brown to #1 terminal. Ground the alternator also is a good idea. The bigger RED wire stays just as it is.

[VetteVet]

This thread should explain it all and help you out.

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

[maverickmk]

Originally Posted by Andy4639

Thanks you sir, it's nice to hear when you help someone out.

For a stock truck to add the internal regulator it's pretty simple stuff.

Vett has made several post showing the stock wiring and the new wiring for this mod. Most people just jumper the external regulator out and use the old wires. I like how Vett and I do it. Thanks Vett for the diagram pictures.

Cut the connector off at the external volt regulator and the white wire can be took out just clip it off and for get it. Strip the tape back on the harness to where you have enough wire for the brown wire and red wire to make it over to the alternator. Hook them up as in the drawing. The red goes to #2 terminal & brown to #1 terminal. Ground the alternator also is a good idea. The bigger RED wire stays just as it is.

If I understand this correctly, the only thing added is a new run from the alternator to a junction block then a fusible link from the junction to the battery and a pigtail that fits the new alternator, correct?
I'm going to give this a shot this weekend if I get some extra time.

[Andy4639]

If your doing just a simple swap from the stock external to a new 12 SI alternator. You have 2 choices.
Here is what you start with.

Picture #1 is how it's wired from the factory.

These are your 2 choices. Either one works just fine but I like the no clutter 2 choice better.

Picture #2 is if you just jumper the regulator and leave it all in place.

Picture #3 is how I like to do it.

You strip the black wiring cover back enough to run the brown & red wires over to the alternator and take the external regulator out and the old connector and it makes for a much cleaner look.
You can buy the plastic plug ins for the wires but I just use spade connectors.
Again this is for the 12 SI alternator.

[jamyers]

I'll add that while you can jump the red wire from the #2 terminal on the alternator (last picture above), please don't - you lose the built-in "remote voltage sensing" feature that GM engineered in. Go ahead and run that smaller red wire to the junction point behind the headlights. That way, the alternator is sensing actual Battery voltage instead of its own output.

http://www.madelectrical.com/electrical-tech.shtml has great info.


Also, if you're wanting to keep your vehicle "stock-ish appearing", I've seen guys gut their old external voltage regulator, jump the terminals under the cover, rework the alternator plug according to the above diagream, and apart from the newer-style alternator everything appears original.