PNP Switch for Connect and Drive

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Aug 13, 2020 | 09:59 AM

Zorglub123

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PNP Switch for Connect and Drive

I’m finishing the install of a “connect and drive” LS3 and I’m lost with regards to the Park/Neutral Position switch (PNP). The switch is installed on the 4L70E gearbox, but there are no connectors on either the Supermatic pigtail or the engine ECU to connect to it. From what I can see on the Connect and Cruise wiring diagram, this switch does not exist!

I understand the 7 way connector will give some signals such as backup lamp and neutral safety switch. The second 4 way connector gives a transmission range signal.

Question: I only see a use for the backup lamp, given that all the other controls should be handled by the GMPP ECU or the Supermatic box. Am I wrong? Any advise to where I should connect this switch?

Thanks

Aug 13, 2020 | 10:27 AM

bobcratch

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Quote:

Originally Posted by Zorglub123

typically its used as the ground for a starter relay coil.

Aug 14, 2020 | 02:22 AM

Zorglub123

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I dont think that’s the case for the crate GMPP engine. Any other ideas? Thanks

Aug 14, 2020 | 05:14 AM

bobcratch

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Quote:

Originally Posted by Zorglub123

I dont think that’s the case for the crate GMPP engine. Any other ideas? Thanks

it does not have to be used for anything. The engine controller probably doesn't look at it or care about it. It is mainly used to prevent the vehicle from being started in gear, which is why many use it as the ground for the starter relay. Same goes for the backup lamps. Only used for backup lamps, the engine controller does not care about that signal.

in my swap i do not have or use a PNP switch and it works fine. However, the car can be started in gear, which is not ideal.