electrical gurus unite

I have an 87 and ive been trying to fix my dang driver side window switch for forever it seems. For some reason, I gradually loose power in the switch. The driver front window switch gets 12 volts, passenger front 11, drivers rear 10, and passenger rear 9. The drivers side rear seems to get just enough to eek by, but the passenger side window doesnt. All the windows work when I use the switch that is in the corresponding door, but that doesnt get me anywhere when my dog wants to change the window her head hangs out of.

Ive tried searching and havent seen anything regarding this specific issue. Ive also tried using 3 other switches that I picked up at the local bones yard, but they all get the same voltage going through them. I traced the wires just to be sure they were ok, and they were. Its just up at the switch that I gradually loose power. Anyone know how to cure this?

Thanks,
Jmeti000

any sign of corrosion on the wires or connections? Xjs are notorious for having undersized wiring and the slightest bit of corrosion will keep the current from flowing through them.

All of the window motors draw power through the drivers door switch panel--if you use the switch on the rear passenger door it will draw power through the drivers door for the motor. If you get good performance from the local switches then the most likely explanation for your issue is that the switches in the drivers door panel are weak or have a bad connection. The switches there plug into the block using a bunch of pins into a rubber block, with a little hook to hold everything together. If you have lost the hooks or if they've come loose then the switches will hang loose in the block.

update...after spending all evening unwrapping and chasing wiring, I finally figured out that just seperating the connectors was a much easier way of doing things (not my brightest moment lol). Anyways, it seems the culprit is somewhere in the passenger rear door wiring/connections. I get 12 volts through both wires (dependant on up or down)all the way to the connector that goes to the back door. Once I plug in that connector to the switch, I drop down do 6 volts. Will continue on tomorrow and post up what I find...

Interesting. Keep us in the loop.

Look for a cracked or weakened wire where it passes between body and door. Those wires can eventually fail where they flex, and it can be hard to trace the fault.

Its fixed...I unplugged the motor and plugged back in the switch, which sent the whole thing into a tizzy...hence, the switch had a short in it. A quick trip to the local parts yard for a new to me switch and $5 later the windows all work perfectly. Now all thats left is to wrap the wiring again and put it all back together. Thanks to all for the help..
Jmeti000