GM dual alternator charging issue

[Saltine]

ok, I have a 95 cadillac fleetwood. primary alternator is 240amps, 2nd one i added is 180 or 200amp. the 2nd alternator is reverse mounted b/c of space issues.

heres my issue and hopefully someone can help solve it

plug the primary alt in and it works fine, unplug it, hook the 2nd alt up and it works fine, but if you hook them both up at the same time the "charge battery" light comes on

any help

[81000D]

You have one reversed so it probably wired out of phase if that makes sence to you.

[Saltine]

i have the wires for the plug matched up from one alt to the other...with the 2nd one hooked up with the wires how they are it works fine, it doesnt give an issue till both are hooked up at the same time.

i dont want to swap the wires and damage anything

[81000D]

Yes but you have them wired the same but one is rotating the opposite way so you power and ground are getting revers voltage.

[Kyblack76]

Hmmmmmmmmmm

[Dangrebel]

No. Your car is getting too much current pull from trying to excite both. It gives you a battery light.

[Saltine]

so whats the fix Dangrebel

[Dangrebel]

Add a dual harness relay kit. I got one for you. Pm for more info...

[biscuitownz]

Yes but you have them wired the same but one is rotating the opposite way so you power and ground are getting revers voltage.

I don't think it would matter which direction they're spinning because the output from the alt is a/c anyway, after it goes through the rectifier it should be the correct polarity

[Dangrebel]

Yes but you have them wired the same but one is rotating the opposite way so you power and ground are getting revers voltage.

I don't think it would matter which direction they're spinning because the output from the alt is a/c anyway, after it goes through the rectifier it should be the correct polarity

You are right good sir!!