Out of nowhere this morning, neither the rear defroster nor the AC/heat/blower would work. I swapped the fuse and it worked fine until I turned on my headlights. As soon as I did that, the fuse blew again. Any ideas on where to start troubleshooting?

Side note, in the past some fool replaced that fuse with a 10A fuse instead of a 7.5A fuse and it still blew.

 

Found it. The ebay fog light harness was shorting. Scorched wires. I knew I smelled smoke that day but I thought it was from outside.

 

Good stuff to hear that is it all fixed up. Any clue as to what happened to the wires? Rubbed on something?

 

That sounded really odd... unless aftermarket wiring was somehow involved... in that case all bets are off.