I've been working through some gremlins on my buddy's Jeep, and so far the only issue I have left is fuse 11 in the PDC blowing every time the key is turned. I've been digging through looking for a short to ground, but have not had any luck. With every device I'm aware of disconnected from the circuit, the fuse is still blown immediately. I'll admit finding shorts is not my area of expertise, but I'm now at a point where I'm not even sure I'm grasping the basics of the wiring diagrams considering the behavior I'm witnessing...

Here's where I'm at: while the key is turned to run, I'm getting 12v from this slot in the PDC

If the key is off both get continuity to ground. Another oddity is that fuse 12 has continuity to ground, but is not blown. I did notice that they have a common feed circuit so maybe it has something to do with that. The thing I'm having a hard time understanding is why pin 47 is getting power on its own to begin with. Based on the wiring diagram, it seems that the power to pin 47 should only be supplied from pin 46 when the ignition is turned to run.


Is there something I'm grossly misunderstanding here? It just seems like there's nothing to indicate that circuit f12 should be receiving power on its own, and at this point I don't have a whole lot to work with using my current understanding of the system.

 

I’ve found the issue was caused by an incorrectly spliced wire from when he installed this 1996 harness into his 1995 jeep. I truly feel I understand why mechanics hate when the customer supplies their own parts.