On the switch assembly connected to the shifter what is the purpose of the PARK NEUTRAL SWITCH with blk/wht and orn/blk wires. I know there is a neutral start and a back/up switche incorporated with it.I think those wires are connected to the ECM ??????

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1987 IROC w/T56 and a 383 TPI in the works

 

Nobody knows

 

The black / white wire connects to ground, and the orange / black wire goes to the ECM to indicate park or neutral. The wire to the ECM is grounded when the gear selector is in P or N, and is open circuit in any other position.

Tim

 

Thanks Tim,but what is the purpose of it,I need to know this to complete my T56 swap,do I close the circuit or live it open since I won't be using this switch any more.

 

I'm not sure of all of the parameters that the input controls in the ECM algorithm. One of them is idle speed (higher in P & N). If you get a PROM for a manual trans, then the input is ignored.

Tim

 

So I won't have to worry about it I quess since I'm gonna have a custom prom for my 383

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1987 IROC w/T56 and a 383 TPI in the works