What are these wires for ? 72 GMC

[geunther]

Agree with KWMECH. Wires for TCS solenoid. The green wire is for the secondary temp sensor related to override TCS function, not for the temp gauge. The temp sensor for TCS function was between 6 and 8. So, trucks with TCS had two temp sensors.

[Canadian 72 C15]

Originally Posted by geunther

Agree with KWMECH. Wires for TCS solenoid. The green wire is for the secondary temp sensor related to override TCS function, not for the temp gauge. The temp sensor for TCS function was between 6 and 8. So, trucks with TCS had two temp sensors.

Wow awesome info. Thanks. Ok so safe to say then now that I have an 80’s 305 and soon to be a 350 or something else I can get rid of these wires and will never need to use them again ? Where do they come from and can I unplug them from somewhere in the firewall or somewhere else? Want to clean up the engine bay of unnecessary wires.

[54blackhornet]

I suggest you get yourself a wiring schematic for your year truck. Makes it simple to understand where wires go to and from...

[geunther]

Yes, you will likely never need them unless you like the factory original thing like some of us weirdos. The solenoid got its ground from a couple of different places, one was the temp sender on passenger side (cold temp situation), one was from the transmission (high gear situation). Those wires should be fairly easy to find as you already found most of them. Under the dash there will be a delay relay which supplies to the power side of the solenoid after I think 20 seconds. I can show you a pic of the timing relay as well as transmission ground wire if need be. The wires them selves will be taped together with some of the cowl top wires.