Wiring problems are the hardest to repair. If its blowing the fuse, its probably a shorted wire. Follow the wire if possible. Or check the wire looms in that area, for rubbing, chafing, or maybe it pinched by something that was bolted down or clamped. It takes some time to find these kind of problems.
In the PDC is where the 20 amp fuse keeps blowing (I assume) This fuse provides pwr to the B(+) Fused to the Power Train Control Module (PCM). The ASD (Auto shut dn Relay) is also in this circuit. This provides a positive indication to the PCM when the ASD is activated. This will also generate a fault code.
So it looks like the short is between the fuse, the ASD, and the PCM.
Now you just need to find it. Its probably a intermittent problem and not a hard fault or direct short. Or maybe it is. You will just need to follow the wires and or loom and look for problems and repair the wire. It may be red wire witha yellow tracer.
[FONT=Trebuchet MS]01' Jeep TJ (Jeep #5)
3.5 RE Custom SuperFlex, Raingler, Kilby, Currie, Banks, Borla, American Racing, Custom mods, Always more in the works.