Hello guys.. I did a swap. I tuke my old, 87 irocz 5.7 tpi motor and rear and put it into my 91 rs 5.0 tbi.. I witched the wiring harness under the hood and the computer.. Well I went to start it yesterday and got nothing at all. I got power inside the car the radio works. My feul and oil gauge aint reading, and I know this is wrong when I try to turn on my winsheld wipers it turns on some of my out side lights on the car instead of the wiper... My light switch only turns on the gauge lights.. Can some one help me out...

 

At that point its time to either call summit and get the correct wiring harness from Painless, or call the dealer and get a brand new one. You have some serious issues and its way too much to type...just start over. You may have crimped a wire laying the harness in, or maybe chevy altered the harnesses and connections between 87-91. I'm sure there were differences along the way, best thing is to start over with a new harness

 

If you dont have hands on experience with the swap thats been done, or at least a very good knowledge of whats required, please dont post.

Buying a new harness will get him nowhere, and "painless" doesnt even make something close to the factory harness, just a standalone harness thats pretty much designed strictly for street rod projects with no existing wiring.

litlbabiboi:

The wiring is quite different between 89 and earlier cars and 90-92's, the C100 connector at the firewall on the drivers side is where most of your power feeds are, the 90-92's the wipers are part of the headlight harness, earlier cars its part of the engine harness. You'll need to get the pinouts for each, disassemble the C100 connector and pin it properly for your car.

The C207 on the passenger side under dash may also need a bit of work. You'll need the pinouts to accomplish this properly also.

 

You know you could pretty easily rework a 90-92 V6 harness to be used, and the only thing you'd really have to get is a V8 90-92 TPI prom.