puppy

So the relay in the PDC labeled fuel system relay (#51 in the picture above) is the power supply to the VP only? The lift pump is in the tank with a separate relay, battery power from PDC main stud, triggered from original source. The lift pump comes on when the ground is unplugged, cycle the ground plug a few time and the #51 relay clicks, the truck starts.

Update The truck can be made to run every time by unplugging the ground plug at the auxiliary battery several times and getting the fuel pump relay in the PDC to close, which turns on the lift pump and gives the IP power. Is it possible that this exercise is resetting the ECM somehow and getting it to operate properly? I suspect an ECM problem.

2002 Dodge Ram 3500, 6 speed

Fuse 11 in the PDC is labeled "50 AMP IGNITION RUN/ACC" under the cover. Can someone assist with some diagrams on this circuit?

I know this is a loonnngggggg shot in the dark but. . .I am fairly certain this is the same problem I am having and I am wondering what the resolution was. I have an active thread on the forum btw.

Update: alternator and starter are disconnected batteries are separated 2 plugs at driver side are disconnected 12 volts only going to PDC voltage still present unless PDC fuse 11 is pulled or plug closest to engine on PCM is unplugged I cannot fine PDC fuse 11 on the diagrams.

Truck decided not to restart once Saturday, started Sunday and died once, one restart since then. No rhyme or reason. but. . . I have 8 volts on the grounds at the Aux. battery for the PCM and ECM. Disconnect them with the key on and everything comes on like normal but no start. (no voltage on VP pin 7) Reconnect and it will start. (voltage on VP pin 7) Will restart everytime after you disconnect and reconnect grounds at Aux. battery. Any thoughts?