Popping the radio fuse

Got an older aftermarket radio in my P5. Been working fine until last week. Then it just failed to power up. No big deal, I thought since I was ready to upgrade.

So I pulled the stereo today. Checked the power leads, both switched and unswitched. The switched one is dead. Check the fuse panel to find the fuse is blown.

Replace the fuse, click the switch over to Assy position and the fuse blows again, this with the stereo removed and wire harness adapter removed. So it appears I've developed a short in the factory harness.

That's going to be darn near impossible to trace down, so I'm probably just going to run a new switched lead to the stereo. Before I give up completely though, I'd like to try to trace it back. Makes me nervous having a shorted circuit.

Anybody got a copy of the factory wiring diagram, specifically the section with the under dash fuse panel?