I'm just finishing up my 89 RS / LQ4/ MP-T76 build and I realized that the previous owner didn't even have the alternator wired to anything. The wires just went into the harness and didn't go anywhere.

I'm using a harness from a 01 or 02 F-body and PCM and need to know how to wire this thing up. Any help would be greatly appreciated. I posted this question on LS1 tech as well.

 

The f-body harness will have only one wire in the plug, and one that goes into the back which is 12v.

 

so your going to use the alt. from a pre lsx?


terminal F is hot in run power
terminal S is hot all times... starter cable or battery.. (voltage sensing)

the big stud goes to battery for charging

 

Well, I planned on using it if possible. Will it not work?

Please forgive me for not quite understanding what you are telling me about terminal F & S.

I assume I would run the lug labeled bat to either the starter, a dist. block or straight back to the battery. I just need to understand how to tie the other two leads either into the LS harness or the chasis harness.

 

Again I'm not as stupid as I may appear right now but I still don't get what you are saying.

 

the connector on your alt. has a tan wire and a red wire.. they should be labled as F and S some were on the connector housing or alt side of the connector (FYI that 01-02 harness wont control that alt.)


as for using it with the ls1 eng. it would work just fine as long as you make a bracket or somehow mod the lsx one

 

Thats the 3rd gen alt and your 89 connector

This is correct

Run the S (red) to the power dist block whether its stock on the starter lug or remote
Run F (Tan/wht) to C207 pin D (Tan/wht)

3rd gens mix the Alt and fan fuse into one point for some reason

You wont be able to use the old alt in the new LS1 bracket. IIRC the pulley depth is incorrect. Anything you do will be custom

 

Ok got it! BTW I have already made my bracket to mount it I just wasn't quite sure how to hook it up.

 

Well, problem solved. My idiot light didn't work so I jusy wired a 100 ohm resistor to the tan wire and bam! Thanks for the help.

 

I recently went through this with a 88 camaro and a 95 lt1. I know atleast mine required a 470 ohm resistor. I tried several 100 ohm resistors and ended up subsequently changing several alternators!