So out of the blue, my truck wouldnt start because fuel pump wasnt running.

I didn't have time to diagnose it and just quickly rewired it on an aux circuit.

i did check the socket for the relay and it seemed to have power on 3 of 4 pins which im pretty sure isnt supposed to happen.

Any ideas before i tear in? I was thinking mouse or chaffed wire but could the ASD circuit maybe do that?

 

What year is your truck?

With ignition off, you should only see power on 1 pin, ignition On, two. If you still have power on a third pin, key in either position, there's a problem.... Gotta short somewhere. But, that also depends on if the relay is in the socket when you test, and if the ignition is on.

 

Ya i forgot, a 94 2500.

is there any preferred harness seller for these trucks? Been a while since i bought a harness. Usually make ir repair them.

 

The fuel pump relay is wired parallel with the auto shutdown relay and the PCM uses a common ground pin to activate both. The ASD relay is backfeeding the circuit unless the engine is cranking/running and the PCM provides a ground. If you pull the ASD relay you shouldn't see power on pin 85 of the relay socket anymore.