ok heres the deal. i have an 88 firebird. the dash and all that other wiring under the dash is all screwed up. i got my friends harness, dash steering column out of a 85TA. Will the 85 harness work with my 88 harness under the hood? j/w if i can goahead and install thedash without any problems.

 

I can't say for sure but, 2 things that would be different come to mind and that is, 85 having a mechanical speedo & 85 & 89 headlights have different setups as far as the way the lights are controlled for rasing & lowereing. I'm sure that the harnesses could be modified to use but, as a guess, I'd say they won't directly swap.