ATTN: 92-96ers - try this to fix dash mounted rear window switch issues
If you have other rear window problems, you will need to address those problems individually, as this fix below only pertains to the dash mounted rear window switch on 92-96 Broncos .
Over the past weekend, I finally tackled the rear window on my 94 Bronco.
First, my rear window motor I just installed was brand spanking new, because the old one was seized up (did not even work with a rebuild). I did everything in Steve's folders, read every single thread on here relating to the rear window issues (I mean EVERY THREAD POSSIBLE :shocked ) and still, I had rear window issues where it would not go up or down with the key OR the dash switch.
So, I ended up pulling the entire harness out of the tailgate and from under the truck. I removed all of the conduit to check all of the wires. Every wire was in perfect shape, even where the tail gate "bends" the wires all the time - no issues, no cracks, no burnt or "broken/bent" wires, etc. I looked at the harness connectors. All of the connectors were corroded on the Bronco's harness. I then removed the spades from each of the connectors and cleaned them all off with emory paper so they were all shiny again. I then also sanded down the area of the ground wire behind the driver's side taillight. After doing this, The rear window then worked with the key at the tailgate! I could now get the window to go up or down with the key switch in the tailgate. :chili: However, when I tried to get the window to work with the dash switch, it would sporadically budge a little here and there, but would not operate properly at all.
The next thing I did was to remove the dash switch. After removing the dash switch, I picked up a small flat head screw driver and popper off the "rocker" switch cover from the main body of the switch. I squirted electrical contact cleaner all over the contacts within the main switch assembly both on the front and back. After doing this, I then snapped the rocker switch cover back on the main body and plugged it back into the dash harness. After doing this, I was able to get the window to go down, but not up.... :wacko
I removed the switch again from the dash harness and again removed the rocker switch cover from the body of the switch. I noticed there are (4) contact points for each copper tab within the switch (1 copper tab for "up" and 1 copper tab for "down). (2) contact points for up, (2) are for down. These contact points really resemble a "points" ignition system on an old car, where there is a small metal disc attached to a flimsy piece of flat metal (in this instance, copper) and the two discs make contact to generate a spark or electricty. If any of you know about a points ignition system, the contact points eventually get "burnt" or worn due to the constant electrical pulses when the system is operational (or in this case, when the switch is depressed up or down). To remedy this, I took a small jeweler's flat head screw driver and carefully scratched the surfaces of all (4) contact points. This in turn removed the corroded or burnt surfaces and revealed "new metal" from under the worn surfaces. After cleaning the contact points, I then squirted the electrical contact cleaner all over the switch front & back again, popped the rocker switch cover back onto the main switch body and reinstalled into the dash.
Now I was able to get the rear tailgate window to go UP and DOWN smoothly!!! I tested this multiple times, over and over - with KOEO and KOEO, the switch worked flawlessly like new again! :rockon
I had (2) of these rear tailgate window switches and did the same procedure to the other switch that was "dead" and that switch also now works.
So - for those who are having intermittent rear window problems when using the DAS MOUNTED REAR WINDOW SWITCH - try the above FIRST, before spending the $$$$ for a new switch or going crazy... I'm not saying this is the cure all for everyone, but I have a feeling everyone else's dash mounted switch may have the same wear on the contact points.
After getting the dash mounted switch to work again, I then reinstalled all of the rear tailgate harness again and made sure the rear key switch operated the window and the dash switch worked the window - and both locations work now 100%!