Working on a 1994 E350 7.3 with ambulance package. I bought it last week, nonrunning condition, hoping to get it to run.
A rodent chewed up some wires under the hood, and I was able to splice them back together.
Charged up the batteries for a couple of days and installed them back in the van.
But I have no power anywhere. No lights work, horn no work, nothing.

I can get the motor to turn over at the starter relay by using a small jumper wire from the positive terminal to the little signal port. So I have enough power to do something.

Also from the starter relay there are two small wires that join into one larger wire----I believe these go to the glow plugs.
There is also a fusible link leading into a yellow wire. Not sure what that goes to. I cut off the fusible link and hooked it up straight just to check--- still no power anywhere.

I am getting 12V at the starter relay positive. I have checked it using the battery ground and using the engine block as ground. 12.2 V either way

I figure I can start unwinding wire looms. Seems like there is a blown fusible link for the main power. Hoping that someone can point me to where it is or perhaps what color it is, anything.

Any suggestions?

 

There should be a large fuse box located in the engine compartment near the master cylinder. Check for power and blown or missing fuses. Someone may have robbed parts for use on another vehicle. Also need to check for voltage at the alternator.

 

I had already confirmed that all parts were present, but had no voltage to anywhere in the PDC or in the fuse panel in the cab.
I found the inlet wire to the PDC (in the engine compartment) was a large (4 ga?) wire which terminated onto a lug that contained only one other wire, a red wire (6 ga).

I finally had the time to trace this red wire back through the firewall and into the cab. It went under the drivers seat to a "kill switch" which was turned to off. Turned it on and everything works!

I feel a little silly, having been stumped in this manner, but I didn't know, and now I do, so lesson learned.

 

Good to hear that you found the problem!