84 -86 engine side -firewall harness plug
 

i got a 83 chevy k-30 chassis -that i put a 85 &later chevy cab on it -is the engine side of the 83 firewall harness plug differant -than the 85 & later cabs ? i cant seem to get turn signals & have gremlins sometimes ? it just seems like the plugs are in differant spots ?? also seems like if i jiggle the inner side of plug-some of the stuff works-sometimes ? both sides of plug look alright !i thought id ask -before i dig into it further ? thanks for any info

Re: 84 -86 engine side -firewall harness plug
 

I think 81-87 bulkhead wiring and connectors are all the same. I know from experience 84 to 87 is pretty interchangeable, the whole front light harness was the same for me on a swap from a CUCV which is base on the 84 model year to 87 swap I did.

Here is the wiring diagram, and more here: http://forum.73-87chevytrucks.com/sm...?topic=11766.0

http://www.73-87chevytrucks.com/tech..._V8_engine.jpg

Re: 84 -86 engine side -firewall harness plug
 

That's the one-size-fits-all diagrams from the back of the Haynes manual. One size most assuredly does not fit all.

You really need to know what year the cab harness is setup to service. Bulkhead plug pinouts varied almost every year. Some positions changed and others stayed the same.

Download the 1983 & 1985 (assuming it's a 1985 cab) GM wiring diagrams from the link in my signature and look at the pinouts. Re-pinning the mating plugs is not a big deal if it needs to be done.

The bulkhead plugs contain the GM circuit numbers. You'll find a circuit number table in the front pages of some of the GM wiring manuals... I believe 83 s one of them.