Power Window Fuse blowing
 

I have an 87 Cab and the windopws were working fine albeit the passenger window is slow to go up. Now the windows are down and the fuse keeps blowing. I registrer 12.5 v on the window fuse terminals with the key off as opposed to zero. I pulled the switches out and they look fine. I really don't feel like taking the doors apart again. Any ideas to troubleshoot? My Bently book was mistakenly thrown out ( not by me).
Thanks
Eric

Solved
 

I removed all the switches and then tightened up the screws on the fuse bar. The voltage across the window fuse dropped to zero with the car off when I tightened the screws. Then I replaced each switches to determine if one was bad. It turns out one of the passenger switches was bad and causing the short. The passenger side is a pain because you need both switches to work the window. If one is missing it wont go up or down. So I had to use the two good switches to make the window work. Then I remvoed one of them and put it into the driver side window so I could at least use the window till the new one arrived.

I had purchsed from Pelican both the APA brand window switch and the Kostals switches in the past. The one that was bad was the APA. When I opened it up there was corrosion inside the switch and the contacts were welded at the opposite ends on one of the rocker sides. Something that is not supposed to simultaneously happen normally and that caused the short. I would recommed the Kostal switch ( it has the part number printed on it vs the APA which bears no markings) .

Eric

I had the same problem. It seemed that when I open or closed the window the movement was very slow and the motor was really laboring. I removed the door panel and lubricated the tracks of the regulator with lithium grease. That solved the problem for me.