So for a few years now I've been crawling over my seats with my jump box to make my rear glass go up or down after it randomly quit working. I've finally gotten sick of it and want to be able to use my switches instead of having to jumper the motor so I went and messed with it for a few hours today.

Here's what it does.
Neither switch will operate the back glass. The switch in the dash is good, I've checked the ohms readings while using a diagram and it checks out good. I've also checked ohms reading from the 2 black wires on the back of the switch down to the ground under the drivers side kick panel and they also check out good, so the grounds for the switch should be good (unless my test procedure was wrong). I have taped the switch in both the up and down position and used my test light on the 2-wire harness that goes to the motor. Both the red/yellow tracer and yellow/red tracer wires are showing power, not at the same time though. One will have power with the switch flipped one way and the other will have power with the switch flipped the other way. This means I have either a ground problem, or the tailgate key switch is faulty, correct?

I have taken the whole back glass harness out and checked the ohms readings for the key switch. I get a reading of .5 when I put my test leads on the black/white wires, but I don't get any readings when putting the leads on any of the other wires, or I don't think so at least. I've honestly already forgotten. I've read countless threads and seen many wiring diagrams but I just can't figure it out

So if anyone has any suggestions, that would be awesome. And I'm sorry for posting one of these threads, you guys are probably tired of them since this is a common occurrence with these Broncos. FYI mine is a 92 if it makes any difference

 

Also both fuses checked out good as well. And I used a jumper wire to jump the safety thing on the drivers side of the harness.

 

I'm not tired of this thread again because my key switch lowers the window about 1% of the time. Dash switch and key up are perfect.

Two separate questions for you. When the harness was out did you test the two key switches? Have you checked for broken wires between the tailgate and the body where the harness bends? There is a connector behind the driver's taillight that might be a good place to test with the front switch taped again.

 

For me only the key works... so don't worry, nobody is tired of these threads.

 

No, the switch is functioning properly. The switch reverses the polarity on power going to the tailgate glass motor. So, when you press the switch one direction one wire is positive and the other is negative. When you press the opposite direction the wires switch polarity which reverses the direction of the window motor. All power window switches work this way.

 

I honestly don't know how to properly test the key switch, all I found was how to test the dash switch. And I've tested the harness from the male pins inside the connector all the way up TO the key switch and they check out fine, there' no breaks in the wiring.

I've heard mention of another ground location, at the back of the Bronco on the cross member that holds the rear of the tank up. I can't seem to find this ground and I'm willing to bet that's probably my actual issue

 

Oh yes I know this, I think I just worded my statement bad. I knew that it was supposed to switch polarity, but with it switching power and the window still not operating, I was assuming I had an issue with the ground path.

Could you tell me the location of the ground at the rear of the Bronco? I've heard that it's supposed to be in the middle rear of the Bronco, somewhere I also read that it's supposed to be offset and even somewhere I heard it was supposed to be in front of the gas tank. I can't seem to find any reliable information since I can't find this ground

 

Got it!
All that checking I did was pointless. The connector for the motor had corrosion inside it. For some reason, my jumper wires worked perfectly in it but the actual wires from the wiring harness weren't making proper connection. So I took the connector apart and cleaned it up and I have a perfectly working back glass now. This fix took all of five minutes, and I wasted hours of my time tracing the harness, checking for any breaks in the wires, and checking the switches and fuses -_-

 

Take your dash switch out and with the key on or on accessory, make sure you're getting power to the blue/black wire. If you're not, that'll make it to where your dash switch won't work. That could be it or your switch could be bad.

Here's the two wiring diagrams that I found most helpful to me online. The top one shows you which posts on the switch should show continuity when the switch is in different positions

 

88LX5.0H thanks for the two diagrams. Am I thinking correctly?

'94 Tailgate key switch lowers window 1% of the time, sometimes completely, sometimes 1/4". Key up and dash switch work perfectly. A couple of you gurus said on another thread it has to be a faulty key switch. I can't find a replacement switch anywhere.

Here is my thought...could it be a faulty dash switch i.e. when the dash switch is in neutral and the key switch down is pressed perhaps the P/LG does not ground through the dash switch? Taking it farther, maybe the key up switch is not grounding to P/LG when neutral? This is getting deep for me. I think I am narrowing my search to three switch contacts and P/LG.

Your thoughts please...

 

No resolution yet but I think I eliminated the dash switch and P/LG wire to tailgate. I opened the wrap at the bend between the body and tailgate and probed the P/LG wire. Then connected a jumper to the battery "+" and read 12.4 volts.

Now I suspect the ground contact in the dash switch and the ground wire the key down switch uses are good.

Back to the tailgate key switches, yes there are two on one assembly. Either the up ground in neutral is bad or the down hot (or maybe both).

Anyone know where to find a F2TZ-14529-B ?

Thinking about usage. I like to use the key switch for down a lot but usually raise it later with the dash switch.

 

Your problem sounds very odd. I wouldn't even know where to begin to be honest.