ok I installed a keyless entry system the other day, and it has a horn honk function. as of right now my horn doesn't honk when I use the steering wheel buttons (bad solder points have yet to be fixed). my question is witch wire comming out of the cpu to the horn unit up front.

thanks
alex

 

On my car it is a Green/Orange wire. I have an 88 TII. Hope that helps

 

i have an 86 GXL BTW.

ok thanks i'll check it out

 

uhmmm can you look through the fron grill at the horn? the wire should be comin off of there id imagine

 

I think he was talking about from the ECU to the control unit.

 

Actually its the CPU, the ECU controls the engine.

yes I would like to intercept the wire inside the cabin.

 

You probably already have figured out what to hook it up to id just thought id throw in a problem i found with my FCs horn. Anyway it wasnt working either, the problem i found was on the electrical board in the ECU located in the drivers kick. The connection had been fried. Have absolutely no idea how it happened so i just soldered a jumper wire across it. Works great now

 

I think you mean the CPU , the ECU is on the passenger side. ANyway I was just gonna post asking how to repair a non working horn (which the faq says is usually bad solder in the cpu). Exactly what did you do? Have any pics? Im gonna do it on a spare cpu and just swap.

 

Yep, that is right... the CPU (body computer) controls the Horn (and the warning buzzer, and key lights, and alt failure, etc) while the ECU controls the engine (hench the name Emissions Control Unit or Engine Control Unit).

The main board in the CPU is whcih one you would want to repair. Generally when the horn goes, you would want to remove the solder on the circuit board where the main plug (largest) goes into the CPU (middle of the CPU). Then reflow new solder into the joints. Sometimes the CPU will also require the Horn relay to be replaced. If there is a lot of carbon scoring on the contacts you would probably want to do that.

I can also rebuild the CPU if you would like, or sell you an already rebuilt one from my webstore.