Hi my tail lights are not currently working and i believe it is the CPU that is bad well the stoplight part. my friend currently has a part car that i can take the CPU out of. my question is if i take his cpu can i just swap it into my car or do i have to tune it or something

 

Have you checked your stop switch?

We need more info on yours and your friend's car to determine whether or not you can swap CPU's.

 

I believe it may be your brake light switch.

Not that this answers your question but the numbers on the ecu will tell you what the ecu will fit. I searched the forum a few minutes ago trying to see if someone posted the different models each ecu supported.

 

Great minds think alike lol

 

my car is a 86 and his a 87. havnt checked the break switch but its to dark now ill do it tomorrow

 

Have you Checked the Illumination Fuse?..Start checking Fuses,Under the driver's side Dash,in the Upper corner..the CPU is a Sealed Unit,(flashers,signal,horn).you don't Tune Stuff like that.If it goes,it goes.It has Nothing to do with the ECU(which is for the Engine)..the Brake Switch is on the Pedal assembly Up top..also Check the Wiring Harnesses at the Rear of the car,in the Spare Tire Well(approximate locations,just off to each side,inside there).I honestly think it is a Fuse though.

 

A simple test in the FSM will tell you exactly whats worng. Page 15-46, all you need is a test light and 5 minuets.

Just to clear up some confusion the CPU and ECU are two diffrent things. CPU behind drivers side kick panel next to the fuse box.

 

i checked all the fuses and they are all good and the break switch is fine to the dash warning light is not going off either..so idk

 

Did you look at the FSM yet, again page 15-46. 5 minuets and a test light.

YOU WILL KNOW WHATS WRONG

 

i have the Haynes manual but i dont think i have that

 

The CPU's should just swap out, but I don't think that's the problem. IF you meant Stop lights, then maybe the CPU.

Are your front side marker lights and Front parking lights out also? And I took tail lights to mean just that. NOT the stop lights.

Not the CPU if you mean Tail Lights, front and rear side marker lights, licence plate light etc.

If you have the instrument lights working in the instrument cluster working, then it's not the fuse.

Here's a OLD jpg of the light switch. You can see there's a RB or red/black wire that feeds the tail lights from the switch. It Also feeds the front side markers/front parking lights and other *stuff*. If all these things don't work, then the feed to the RB is bad for some reason.

Anyway, you can see from the attached jpg, that if your instrument cluster lights work and your tail lights etc don't work, it would make sense to pull the plug off the light switch, and then jumper the WG or white/green wire in that plug, to the RB wire in that same plug and the tail lights etc should come on. IF they do, then it's a light switch problem.

 

sorry about the misunderstanding my stop lights dont work everything else works except them. I have checked the fuses and the actual light bulbs and they are fine as welll as the sockets they sit in.

 

The switch on the pedal or the CPU then. You've a spare CPU. Put it in. Just plug it in and don't bolt it in, just to see if that works. Look at the switch while your down there.

 

Brake circuit in the CPU is the 4 pin plug on the bottom

 

You could pull the plug off the brake pedal switch and just jumper the two sockets with a piece of elect wire and see if the lights come on or not. Five minute job.

 

ok thx all i figured it was the cpu i just needed to know if i could transfer the 2 without problem..