Rear window doesn't work with key switch

[broncobob58]

I had the top off my Bronco since June and finally put it back on the other day.When I went to put the window up with the key switch nothing happened,but when I used the dash switch it worked fine.I put the window about half way up with the access cover off and pushed the buttons on the key switch,nothing.I took the taillight off and probed the wires for the window and none of them were hot.The only thing I did since I last used the rear window was replace the gas tank.I even checked both circuit breakers on the panel and replaced them with fuses, same thing nothing.I was also wondering what wire should be hot all the time at the connector in the taillight area?

 

[miesk5]

yo Bob,

and, Welcome back BOB

I know it was a bad time for your family recently..hope all will be good!

You have an 89, right?

Here is da overall skinny;

Repair Synopsis; "...Be aware that: The tailgate latch switch on the driver's side seems to be a common problem, check it early. It keeps the window from being moved when the tailgate is open, & if not latched right, it'll keep the window from working at all. Try pushing the driver's side of the tailgate in while holding the button or key switch in the up or down position. If that makes it work, check out Steve83's How to align a Bronco Tailgate http://www.fourdoorbronco.com/board/showthread.php?t=5224

Ground for the motor connects up front, & at rest runs from there through both switches & both wires to the motor. When either switch is operated, 1 side's ground is disconnected & replaced by hot at that switch. Ground for the motor is not connected to it's case, but supplied through the wires.

There are 2 seperate power sources & 2 fuses/circuit breakers for positive as you know. One for each switch. The same 2 wires are used throughout for both up & down (Polarity is reversed by the switches). When the tailgate is open, you have to close the driver's side latch for the window to operate. Remember to open it before closing the tailgate.

Testing: Does it make any noise at all? Like the motor's turning, but the window doesn't move? If so, there are torque pins in the motor's drive gear that commonly break & aren't too bad to replace. See the torque pin, Steve83's links. If it makes no noise, then it's probably in the electrical system. ....

Wiring Diagram (color codes are correct)

Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums http://broncozone.com/topic/19828-tail-gate-wiring-diagram

To test the electrical system, remove the access panel from inside the tailgate. Run test wires from the battery directly to the window motor connector (Yellow & red wires coming right out of the motor) to confirm that the motor works.

it should be positive to red, & negative to yellow. Be ready for the window to move, keep hands & wires clear. Make all the connections but 1, then connect & disconnect the last wire quickly to see if it tries to go the right way. If it tries to go the wrong way, reverse the wires (This also makes it so that you can lower the window & get the tailgate open to continue testing).

A- If it runs & the window moves when wired directly to the battery, perform the following tests: A.1- With both switches at rest & the latch switch closed, connect a tester between the positive test wire from the battery & each wire from the tailgate loom at the connector for the motor. Both should read 12v. If they do the ground is good.

If they don't, refer to Seabronc's wiring diagram linked above to trace it down, or tell us what you find.

A.2- With the latch switch closed, connect the tester between the negative test wire from the battery & each wire from the loom at the connector for the motor. The red wire should read 12v when either switch is in the down position, the yellow wire should read 12v when either switch is in the up position. If they don't, refer to Seabronc's's wiring diagram linked above to trace it down, or tell us what you find.

A.3- If everything tests ok, but it still doesn't run, there's a couple more possible causes to check: -Sometimes the connector for the tailgate motor will test ok, but not make contact when plugged in. You might try backprobing the motor side wires with the plug connected. On mine I removed it & soldered the connections. -It's possible for a damaged wire to carry enough load to show 12v on a tester, but not enough to operate the motor. Look for worn areas, especially in the loom between the body & the tailgate.

B- If it runs but doesn't move when wired directly to the battery, in addition to your electrical problem, the torque pins in the drive gear are probably broken too. Run the electrical tests in section "A" above, & see the torque pin, Steve83's Tailgate Tech, & Adrianspeeder's links above for the torque pin replacement.

C- If it doesn't run at all when wired directly to the battery, it sounds like it's time for a new motor. See Steve83's

link ... & use the info for removing & replacing the motor. On my truck there were multiple bad connections, so it was hard to isolate the problem. Someone before me used a ton of crimp connectors . Basically I ended up removing them & soldering all the connections, & eliminating the corroded plug to the motor..."

Source: by ElKabong (Ken, El Kabong)

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"...The Bronco tailgate window circuit is a common (Ford) polarity-reversing circuit with 2 switches. Each switch has its own power feed; the dash switch through the ignition switch (key-on only) and the tailgate key switch from the battery (always hot). The dash switch normally holds both motor wires to ground, and the key switch normally holds the motor wires to the dash switch wires. When either is operated, it sends one of the wires hot, powering the motor (assuming the latch switch is closed). When operated the other way, the polarity is reversed, reversing the motor's direction. Neither switch is a "master" because neither will work if the other is in the opposite position..."

Source: by Steve83

Connector Locations Diagram & The Test Procedures in a 90

Source: by RFR (Mark B) at http://web.archive.org/web/20030511125914/rfr.htmlplanet.com/bronco/journal/journal_page08.html

via web.archive.org

---

GL

 

[broncobob58]

Thanks,things are starting to get back to normal.Yes my Bronco is an '89.The window works fine with the switch on the dash,just the key switch doesn't work.I put the window about half way up with the dash switch and then tried the key switch in both directions and nothing.I was thinking at first maybe the key switch went bad,but both directions going bad? I checked the circuit breakers on the dash and then probed the wires in the connector in the taillight area,none of them were hot.I was also thinking that maybe I disturbed the wiring harness when I changed the gas tank.I'll take a look at the diagram and then check the wiring.

 

[Seabronc]

Real quick, if it works with the dash switch, then most of the common problems can be eliminated. Tat leaves the fuse, black with white stripe wire or the key switch. Take a volt meter and see if you have 12V on the black with white striped wire. It is supposed to be hot at all times.

Good luck,

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[broncobob58]

I checked the black&white wire at the harness with a volt meter and got a reading so now I know it has power to the back but it is still not working.I unplugged the connector at the taillight and checked continuity between the black&white wire and the other two wires in the connector.When I turned the key switch in one direction I got continuity in one pin and turned the switch in the other direction and got continuity in the other so I think that is telling me that I don't have a bad key switch or a broken wire in the tailgate harness.I didn't see any visibly broken wires by the gas tank.I was reading that the key switch wiring goes back to the dash switch and back.Could it be possible that the dash switch is bad where it doesn't send power back to the key switch but still operates normally?

 

[Seabronc]

Power doesn't go back through the dash switch and back. It is the ground path that goes back through the dash switch. Yes it is very possible that the dash switch is the culprit. Depending on which contact is bad, it is possible for the dash switch to operate the window and the tail gate key switch not work. The dash switch must be making the center contacts in order for the key switch to work. On older Broncos like mine the switch often sticks in the up or down position rendering the key switch inoperable. Before changing it, make sure it is not in the up or down position

Good luck,

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