Trouble shooting power rear window system - 1977 Wagoneer

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Topic author
Blurino
Posts: 8
Joined: Sat Nov 14, 2020 5:33 am

Trouble shooting power rear window system - 1977 Wagoneer

Post by Blurino »

Until a few months ago, both dash switch and key switch worked. Then the dash switch would only lower window, but tailgate switch worked fine in both directions. Then last week, the rear switch would only raise, and then when I turned the key to the lower side, the switch felt "sloppy" While there was little room for the window to go up, it seemed like the rear switch worked to raise the window.
Now neither dash or rear switch lowers window. I took the dash switch out, cleaned it, checked the resistance (0 ohms) in both up and down. Before I installed it, I touched it to the lower part of the dashe to ground the bracket and it worked fine in both up and down. Great, except that when I reinstalled it, it did not work either way. SO I took the switch out, checked the résistance which is still 0 ohms in up and down, and there is power coming from the center red wire in the plug, but when I check for continuity between the brown and tan wires and ground, I have an open circuit in the tan wire, which I suspect is "down". BTW, rear window safety switch has been bypassed.
Any ideas would be helpful, thanks

SJTD
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Re: Trouble shooting power rear window system - 1977 Wagoneer

Post by SJTD »

Assuming this is the later two wire motor you should have open between both the tan and brn wires and ground. To raise the window 12V is applied to one of them and the other is grounded and vice-versa.

With the front unplugged if you have continuity between one of the wires and ground then you have a short in that wire or the rear switch is stuck or internally shorted.

In normal operation, with both switches centered, the rear switch provides a path for both wires through to the front switch which grounds them both. If you move the front switch it applies 12V to one wire while keeping the other grounded.

If you move the rear switch one wire maintains the ground through the front switch while applying 12V to the other
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

runuover86gw
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Re: Trouble shooting power rear window system - 1977 Wagoneer

Post by runuover86gw »

Actually they didn't start using the front tailgate switch with a ground until 79. In 77 the system is grounded through the motor to the body. So, make sure your motor is clean, where you are connecting the motor to the tailgate is clean and you have good grounds in your Wagoneer. If your tailgate isn't grounded properly or if it's oxidized or corroded where you get your ground to the tailgate, then this could be causing some of your issues. Are you having any issues with your rear window defogger?
Josh's Classic Custom Auto Electronics LLC, Owner/Founder
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1986 GW 360/NP229/TF727/Dana 44's
1986 Comanche
1979 Wagoneer Limited 360/Quadra-Trac/Turbo 400/Dana 44's

Topic author
Blurino
Posts: 8
Joined: Sat Nov 14, 2020 5:33 am

Re: Trouble shooting power rear window system - 1977 Wagoneer

Post by Blurino »

Rear defogger works fine if you hold the switch "on" , otherwise the relay kicks out

runuover86gw
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Re: Trouble shooting power rear window system - 1977 Wagoneer

Post by runuover86gw »

Blurino wrote: Mon Jul 12, 2021 7:14 am Rear defogger works fine if you hold the switch "on" , otherwise the relay kicks out
Ok, that is probably just a timer switch issue for the defogger. I just wanted to make sure you were still getting correct power back there. Have you tried unplugging the tailgate window motor and applying 12V directly to it just to verify that it is still working properly? If you do that and it is working properly, then it's likely you have something going on with your rear switch if you said you tested the front switch and it tested out fine and when you try to use the rear switch, it is no longer working. I would start with testing the tailgate motor first, since that is the easiest, then move onto the rear switch. Or you can check to make sure that the red wire that powers the motor in the tailgate hasn't come loose from one of its connections and you still have the 12V going to the motor.
Josh's Classic Custom Auto Electronics LLC, Owner/Founder
https://www.facebook.com/JoshsFSJRelayKits
1986 GW 360/NP229/TF727/Dana 44's
1986 Comanche
1979 Wagoneer Limited 360/Quadra-Trac/Turbo 400/Dana 44's

Topic author
Blurino
Posts: 8
Joined: Sat Nov 14, 2020 5:33 am

Re: Trouble shooting power rear window system - 1977 Wagoneer

Post by Blurino »

It was a boring wire, thanks for the suggestion!
Sorry for the delay.

Topic author
Blurino
Posts: 8
Joined: Sat Nov 14, 2020 5:33 am

Re: Trouble shooting power rear window system - 1977 Wagoneer

Post by Blurino »

It was a boring wire, thanks for the suggestion!
Sorry for the delay.
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