I'm doing a LM7 with the 4L60E tranny swap into my 1977 C10 truck. I'm planning on using the neutral safety and backup switch that's mounted on my steering column. Do I need the range selector switch at all on the transmission or does the pcm get all the inputs it needs from the main connector? I've cut all the wires that were connected to the fuse block ( 2 pink, dk.green, lt.green,and grey) and I'm just not sure if there's something I need to do with them.

 

The little plug with 4 wires tells the PCM what gear the transmission is in. In HPtuner you can select either full range (PRNDL) or just P/N or none. Make sure you have it on full range if you are using this 4-wire plug completely wired to the PCM.


Here is the logic for diagnostics



Now, here is the large plug.


You need the ground wire on the large plug, for the small plug to pull down the PCM's 12v resisted outputs. That wire is "D" Ground, black/white.
The rest are for various purposes, they communicate with the car, not the PCM. So if you have a neutral switch on the vehicle, for example, and it's already wired to the starter relay, i.e. it cranks the engine when you turn the key, you wouldn't need to use the neutral signal/start signal from this large plug.

Backup lamps might come in handy, though.

 

I only have the one large plug with wires on the range switch

to pcm-
black/white
black
white
grey
yellow

to fuse block
(2) pink
dark green
light green
grey

 

Ah that is a later model. I dont have any pinouts for it, sorry. Probably works in a similar manner, 4 wires to the computer and 1 useful ground.

 

Thanks for trying