Rear Window Lift Motor

As i've been digging through the idle issues with my bronco, i decided to test the other features & the rear window lift motor appears to have died on me. I tried to operate the the window from both the dash switch and the key in the back, neither worked.

I havent taken the panel off yet to check for lose wires/connectors, but i'm curious if this is a common issue on Bronco's. Its the first time I've experienced it on mine.

Thanks,

Does it make any noise at all when you hit the switch, or the key? If not then you should unscrew the t/gate metal panel and get a volt meter on the wiring to verify that you're not getting power back there--or that you are. But check the fuse first under the dash.......

yo,

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

Circuit Overview & Diagram; "... 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 (Steve, That dirty old truck) at SuperMotors.net

Connector Locations Diagram in a 90 Source: by RFR (Mark B) at rfr.htmlplanet.com via web.archive.org

REPAIRS - COMPREHENSIVE! Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

for more and those LINKs that ElK cited; see my site @ http://www.broncolinks.com/index.php?index=478

Thanks guys, i'll take a look tonight and let you know what i find.

But yes it is a common problem lol

I too had that problem, bypassed the saftey switch, been working ever since

So i spent my time replacing the TPS sensor and didnt get to checking out the rear window motor or switch before it got dark, but how'd you bypass the safety switch?

Thanks

find the two wires going to the switch. cut, strip, wire together, no more safety switch.just be damn sure before you cut those wires that they do infact go to the switch.

yo,

be careful when by passing it; if you feel you need to bypass; here is a Tailgate Wiring Diagram (color codes are correct) Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

The safety switch is ref to as the Tailgate Window Limit Switch in da diagram

Parts Break-Out Diagrams Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

May as well just troubleshoot the wiring if the latches are closed.

Thanks guys!

I couldn't get the back of the plug off the drivers rear window switch, but after playing with it the window will now go down about 2 inch's when using either the drivers switch or the rear key switch. So now i assume that the motor and switches are operational and i need to open up the rear and take a look at everything.

So i was able to 'assist' the window all the way down and then all the way up. I would run a couple of inch's on its own and then need help for a couple inch's, run again for a couple inch's, and need a little help the last little bit.

I finally got the back panel off, and no vapor barrier and an old for sale sign... Must have been from the guy i bought it from 9 years ago. I'm going to run a couple of the tests that miesk outlined. I'll let you guys know what i find.

So i tried the test where you hook wires up directly from the battery and it worked going in one direction so i stopped and reversed the wires to test the other direction. The motor moved the window for a second and then stopped. I thought one of my wires might have come undone, but checked the connections at the battery and tried the wires again and nothing happened. So i reversed the wires again & nothing. I hooked the motor back up to the wiring harness and tried both the key switch and the driver switch and nothing...

I think i officially killed the motor. Anyone have another idea before i go pick up another lift motor?

Thanks,

That sure sounds like the motor to me. If it will move an inch or so and stop, try going and doing something else for 20 minutes or so. Then come back and try again. If it moves another inch, its definately the motor being burned up.

50joe said:

That sure sounds like the motor to me. If it will move an inch or so and stop, try going and doing something else for 20 minutes or so. Then come back and try again. If it moves another inch, its definately the motor being burned up.

Click to expand...

Yup, if it's not a bad/corroded/loose wire connection, then it's got to be the motor. Fwiw, I think I bought my last 2 at Jeff's about 4 years ago. Cheap and quick......

yo,

While in the tg, check for other problems;

Motor Torque Pin (also called Bushing) Info & pic; "...fixed it for free some fuel line and a few small cunks of a bolt. Here is a closeup of the bad parts. in the points of the triangle there should be 3 round pins. this help cousion the window from motor shock. I cleaned all the old grease out of the motor and the final drive. my final drive was fine so i was going to reuse it. To rebuild for almost free here is all you need. some fuel line and some steel rod or round spacer (this keeps the fuel line from colapsing completely) i cut the fuel line to the height of the drive gear housing and cut the spacers from round stock i had on the bench. the steel spacers go inside of the rubber fuel line. then the rubber fuel line and steel spacers go in the final drive gear.this was a tight fit but not too tight..."

Source: by Michael C (collinsperformance, The Money Monster) at SuperMotors.net

Motor Torque Pin, Door, but same (also called Bushing) Info & pics in an 88 (see his picture titles)

Source: by Adrianspeeder (The OJ Special, The Lariat, The Bronco) at SuperMotors.net

Motor Torque Pin (also called Bushing) & Gear Replacement & Motor Interchange Info

Source: by Ray, Mike & Robert at off-road.com

Glass Roller Installation in an 85 (Shucks Auto Supply. 74402 Dorman Universal Window Roller)

Source: by spikedzombies (O' Black Betty) at SuperMotors.net

Clean the rails as much as you can.

Well damn, been playing with everything the last two days, and the motor seems to be fine. I'm going to chase the tracks and make sure they havent rusted up in area's. Now i just need to get it back from the brother in-law, the steering gear box & clock spring went out while towing a trailer down the mountain pass, talk about a fun could of minutes!

Thanks again for the help.

is your tailgate rusted out at all? I know mine was, the support for the window/motor, was rusted off and keeping the window from moving all the way up and down, luckily i had a rust free parts Bronco, swapped tailgates and had no problems. Just an idea...

So it’s been a while since I've been on here, unfortunately life gets in the way of playing every now and then...

That being said, i've gotten back to working on my Bronco and can’t seem to get to the bottom of the tailgate window issue. Here's what I’ve done so far:

- Cleaned window tracks and lift gears

- tested lift motor straight off the battery, moves up and down just fine (reversing the negative and positive feeds for up and down)

- I took off the dash panel in the cab to get to the drivers switch and all wires have solid connections

- I peeled back the protective coating on the wires between the tailgate and rear quarter panel. Found a couple chafed wires, but nothing broken.

- The chafed wires where the up & down wires from the drivers switch (purple/green & purple/blue). I tested both wires for power while the key switch was on run and holding the drivers switch in the up and down positions. Each wire had power as they should

- Fixed the chafed wires and moved on

- Took off the latch safety switch and tested, tested okay, will most likely bypass to protect it from failing later

- Looked for other lose connections or chafed/broken wires, but didn’t find any

- Reconnected the final plug to the motor and tried both the driver and rear switch, but nothing to the motor.

- Unconnected the final plug and tested for voltage while operating the drivers switch and received 11.5 to 11.6 V on each wire (test both up and down on drivers switch)

- Reconnected the plug and tested via drivers switch and nothing.

- Tested lift motor directly off battery power & it worked fine.

I’m lost on what to try next. The Lift motor works straight off the battery and I seem to have power to the final connecter when tested, but nothing once I try it when its all hooked back up. Any ideas?

I've been through many of the other posts, and tried a lot of the tests, but I'm just about beat on this one...