PCM underdash wiring
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Joined: Jul 2023
Posts: 118
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From: upstate NY
Car: 1989 Firebird
Engine: 2001 5.7 LS1
PCM underdash wiring
Would the purple wire from my C100 TCC go the the purple wire supplied from my PSI harness underdash wires? Also is there a wire that I can tap into for the neutral switch coming out of the shifter consul automatic? I found out from PSI that the orange wire is not used, I was told that its only for crank testing. Also the safety switch is still run by the car side not the PCM. Does anyone know if this purple wire from the c100 would have 12v with the brake off?
Thanks Rich
Last edited by upstateRich; Apr 16, 2026 at 04:07 PM. Reason: found more information
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