2001 F550 Superduty 7.3L DIT. Here's the history.

Pulled codes for P0221 (no throttle response). Truck absolutely wouldn't accelerate. Also, non op instrument cluster, o/d switch, pretty much everything on the circuit.

Ok, so, replaced the IVS and accelerator pedal, and replaced blown fuse. Temporarily fixed it, for about 50 miles anyway. Now, blows every time you turn the ignition to run..

Haven't gone too crazy yet, but did disconnect the following:

GEM Module
PCM
IVS switch
O/D switch
RELAYS on the circuit.
Now, I get power to the fuse coming in, but the second that I put a fuse in and turn the ignition to RUN, it blows!

Just doesn't make any sense. I've disconnected EVERYTHING!!!!! The only time it doesn't blow is when I disconnect the connector at the I/P. Oh, and also when I pull the power feed MAXI fuse it doesn't blow (of course). Anyway, do you think its a short? Is it before the fuse or after.

Any help would be great. Thanks..

 

If it's popping the fuse it has to be a short.

Of all the things on that fuse, I think I would start by looking for a pinched wire in the steering column that could be grounding out. The wires in a tilt column get moved more than most other places, but I wouldn't rule out the same thing down around the pedal assy.

 

Figures that that little fuse is tied into like 10 things! Yes I agree, I think it is a short to ground too. Trying to narrow down the circuit is proving most interesting, if not just plain aggravating!!! Thanks for the tip..

 

If you've saved one of the blown fuses, try soldering a wire to it and install it so that the wire is on the shorted circuit side. Then connect an ohm meter (multimeter) to the wire and ground. Then move the steering wheel, the tilt, wire bundles or try disconnecting items on that circuit till the impedance goes up.

 

How hard was it to disconnect the GEM and PCM? I still have my stray draw that runs my batteries down if I let it set too long. If I pull that fuze my draw drops to about 50mA.

 

The PCM is easy. It's the big 104 pin connector on the engine side of the firewall down below the brake booster. Loosen the 10mm bolt and it pulls out easily.

The GEM is plugged into the back side of the central junction box, it's a little bit of a pain to reach unless you unbolt the fusebox and rotate it around a little.

 

Thanks Cookie.

 

Wow, so, I disconnected the central junctionbox completely. Then took off the GEM module. Then plugged on (1) side of the central junction box (without the GEM moduel attached to it). Then plugged the 10 amp mini fuse in, and everything was ok. Then I reattached the GEM module, and again, everything was fine. Then I reconnected the other wiring harness connector into the back of the central junction box and it instantly blew the fuse. That wiring harness side is the side going to the battery fuse box. My god, what a pain.

 

Yuck....Chasing ghosts is the worst!!! Good luck catching yours.

 

Yep, thanks, I'll need it!

 

My dads ol mechanic trick is to put a buzzing circuit breaker in there that resets until you find the prob. Although I dont know how long you want to do that. Ebay has a guy on there that sells the superduty dvd so you can track your wiring harness. I got mine for 10 buck or 20. Well worth it the first couple of times ive used it.

 

Not sure what I'm going to do.....Still pulling my hair out! Tracing it through the firewall right now. Thanks, will let you know.