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Devil Dog
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165 Posts
Discussion Starter · #1 ·
Bought a 77’ Formula, and these wires were cut as seen. Are they necessary for anything to get the car running? I’m thinking MAYBE they go to the AC box or something, but couldn’t find anything online to verify.

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DELCO NERD
1993 Pontiac Firebird Trans Am, LT1 5.7L V8
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What colors are they?
 

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Yes, AC harness. It's separate to the main harness so not a major drama to replace. Annoyingly, there's a plug just on the other side of the grommet but looks like they wanted to keep firewall sealed. There were a few variations and changes during 77 and early 78 with changing of switch locations and air sensors, but can be made to work. Just need to confirm with other harness layout/plugs if it was early or late harness. Don't go off shop listings without confirming elsewhere. I noticed even when looking this up that they have another ad of similar but wrong pic.

Do you have a 77 wiring diagram/Service Manual?

It would have been similar to this. In 77 they introduced different engines and layout so kept adjusting things to suit instead of one single harness.



This would be on the dash side connected to it, runs to heater controls and main harness. 78+ is very similar but a wire or two in different locations so best to check plugs and arrangement to know which version you have. I think it was a late-77 change rather than day of new model.

 

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Devil Dog
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165 Posts
Discussion Starter · #5 ·
awesome, thanks everyone for the replies. I won’t be using AC in the car. I bought it with the wires cut, so I just wanted to make sure they weren’t essential to running the vehicle. Just dropped my engine in today finally so it’s good to know that I don’t need those wires
 
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