Passenger power window only goes down. New motor.

Electrical & Ignition

  1. jogirob

    jogirob Well-Known Member

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    Here's a strange one. I guess by coincidence the old motor only functioned one way (tested it when I pulled it out). I replaced the motor and now the window goes up and down when power is applied directly. However if I do either passenger side or driver side switches, it will only go down. This is the passenger side window.
    In the morning I'll stick a test light to the harness where it connects to the new motor's pigtail and see if I get anything on the switch UP position. Off the top of anyone's head any idea what it could be? Would a bad window lift safety relay cause this? Driver side functions normally.
     
    Last edited: Sep 15, 2018 at 7:30 AM
  2. dan juhasz

    dan juhasz FBBO Gold Member FBBO Gold Member

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    can you post a schematic?
    when you bench test the motor i'm assuming you are switching the leads to test for reserve operation correct?
    without seeing a schematic and using more modern vehicles as a reference i'd say you have a broken lead most likely in the jamb where the harness flexes upon door opening and closing
     
  3. 451Mopar

    451Mopar Well-Known Member

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    Most likely the switch or connection at the switch connector. I installed relays for my power windows, they take the high current load out of the switches/switch connectors.
     
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    • jogirob

      jogirob Well-Known Member

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      Still working on getting some good schematics. Here's a few more tests I did that makes me believe I have a short before the window switch on the passenger side door.

      Probed the back of the window motor connectors. On window down I get voltage on one lead (pink+black) and not the other (purple+white). Window goes down as normal. On window up I get voltage on both leads and the window goes nowhere. I did a continuity test between purple+white lead and chassis and I get a normal no continuity reading. Continuity tests between pink+black and chassis *does* show continuity.
      I cracked open the switch backing and did some continuity tests between pink+black and it shows continuity with the solid purple wire. Purple+white shows continuity with solid pink.

      Solid pink and solid purple are from the driver side switch most likely. Striped pink and striped purple wires connect from the passenger window switch to the passenger motor. There's a yellow wire that provides the power source.

      I tried disconnecting all wires from the passenger switch other than the power source + the striped passenger side wires hoping to bypass the short but I just got no function at all :-/
       
    • 451Mopar

      451Mopar Well-Known Member

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      It might be your drivers side switch? The issue is all the motors ground through the drivers switch. The switches, in the un-pressed condition connect the top and bottom studs on each side so current can pass through them. This is how the drivers side can control the motors. Pressing the drivers switch will break one side of the pass-through from normally grounded, and apply the power to one of the connections (depending if up or down.) that power flows through to the other (single) window switch to the motor, then back from the motor through the single switch, and back through the drivers door quad switch and then back to ground.
      On the passenger door (or the other single switches) pressing that switch breaks the through connection and takes the power at the center pin (Yellow wire) and sends it out to the motor, but the return path still flows back through the single switch and through the window switch on the drivers side to get back to ground.
       
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      • oldbee

        oldbee FBBO Gold Member FBBO Gold Member

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        Here's a 68 from FSM

        2018-09-16 17.19.54.jpg
         
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        • oldbee

          oldbee FBBO Gold Member FBBO Gold Member

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        • 451Mopar

          451Mopar Well-Known Member

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          Adding the relays is a good upgrade. Everything grounds through the relays, and they take the high current connections off the switches.
          I added the relays to my car around 2000 because none of the windows worked when I got the car. The ground connector on the drivers switch was broken off. With the relays, I no longer need that ground connection, and all the windows work now.
           
        • jogirob

          jogirob Well-Known Member

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          Thanks for the detailed explanation. This makes perfect sense as to why it wouldn't work at all after I removed the 2 driver side wires from the passenger side switch.
          I found this thread to help out with that relay install http://board.moparts.org/ubbthreads/ubbthreads.php/topics/142362/2.html . Need to ensure I get my switches cleaned out good first...at least I'm hoping a good scrubbing is all they need.
           
        • jogirob

          jogirob Well-Known Member

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          The driver side door switch backing is sealed with some type of adhesive from the previous owner. No way to pop it open without cracking off the backing piece by piece. The wire in question though, pink + tracer, was at the edge so I pried that edge up and pulled the wire out just to ensure it's not melted or frayed and contacting the neighboring wire. It is in good condition.

          I don't know if the switch backing was designed this way but the posts the wires sit on protrude out the back and I can see that the post tips were chaffing against the metal door. Having the door switch off the door frame didn't solve the problem though. What voltage and/or continuity test can I do to see if the problem is in this switch? Not knowing for sure I went ahead and made sure the problem wasn't in the plug connecting into the wiring harness.

          I disconnected the switch's 4 pin plug that goes into the cab wiring harness and I did continuity tests on the wires leading into the cab. None of them had continuity with the chassis except for one dark wire, which was probably the ground wire. So this means that the problem is within the driver side door, after that 4 prong plug correct? In fact, the pink + tracer wire remains continuity free until that ground wire from the switch gets connected into the harness.

          20180917_212348.jpg