yo 83B,
WELCOME to the Zone!
Do you have a few bucks to go to a yard and pull one off instead of doing all that work?
Or a new switch by our SPONSOR HERE JEFF's BRONCO GRAVEYARD!
Rear Window Switch On Dash
or if Image isn't allowed to be shown here;
http://broncograveyard.com/images/catalog/zoom/7879WINDOWITCH.JPG
# 34576 New 1980-86 Ford Bronco Price: $31.00
If you need a yard search on-line I use;
ADP Hollander - My Part Shop® used parts finder - their site is messed-up right now
or
http://www.car-part.com
One quick search shows only a 91 Bronco @ Allied Auto Wrecking, Inc. USA-NH(Weare) E-mail 1-800-529-5865
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Next to troubleshoot is;
Wiring Diagram (color codes are correct)
Source: by our good friend, Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums
Wiring Overview (no Colors codes, but Mark shows relation between both switches, latch switch and motor) Source: by RFR (Mark B) at rfr.htmlplanet.com via web.archive.org
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Switch, In-Dash Test Source: by my good pal BroncoJoe19 (Joe) at Ford Bronco Zone Forums
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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 linked below. 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. 1 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 & Adrianspeeder's ... links. If it makes no noise, then it's probably in the electrical system. Fireguy50's wiring diagram is linked.... 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. To lower the window, 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 Fireguy50'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 Fireguy50'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)
and to complement that;
"...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
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Motor Tester Source: by Michael C (collinsperformance, The Money Monster) at SuperMotors.net
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or as you suggested;
Constant Power for the Tailgate Window Source: by Keith L (TTB Blows, Bling-Bling) via Chris B (Blue, bronco boy) at telus.net
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Motor Replacement; "...If the motor runs but doesn't move the glass, push the glass up for access. The glass is strong enough to support its own weight fully extended, but no extra weight..." miesk5 note, I use a standard height saw horse with a blanket folded to support da glass.. make sure the tailgate is resting DOWN fully (horizontally) by pushing or sitting on it before pulling glass out by hand (or closing driver side Latch by hand and using Key sw or driver's Dash switch to energize motor) and sliding saw horse under da glass...the cables need to fully stretched...& in his #7; "If the motor doesn't run, remove the 4 nuts (2 on each side - see below) that hold the regulator tracks to the glass brackets. Bend the regulator arms down slightly to pull the studs out of the brackets, and then push the glass up. Remember to FULLY lower the glass before lifting or closing the t/g..."
Source: by Steve83
