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Posted

I have a 1994 Lexus LS and the r/rear window stopped working. How do I check and see if the motor or switch is defective? Window does not operate from the driver's control either.


Posted
I have a 1994 Lexus LS and the r/rear window stopped working. How do I check and see if the motor or switch is defective? Window does not operate from the driver's control either.

Sorry, no direct answer yet, just a bunch of questions:(but it will get the thread kick-started and the juices flowing) ;)

And you do not have the "child" lockout button depressed, right? (all the other windows work properly?)

Was the offending window working properly up until now? Or was it sometimes sluggish? Do the interior lights dim(ever so slightly) when you

attempt to run the window?

You may have to remove the inside door panel and start checking with a voltmeter.

Posted

have complete silence and press on the switch and see if you can hear the window motor. if you can then the window's off track if not it could be the switch itself or the motor.

Posted

Unplug the motor. Place a 12-14V battery from a drill to the motor directly, providing power. If it does not move or sparks, the motor is bad.

Typically if neither switch works, it is the motor. My '92 driver rear wouldn't roll up from either switch, but would roll down fine. That was a bad switch. Since power feeds through the sub switch (on the rear door), it's likely the motor is dead if neither leg of the circuit is doing anything.

Posted
if it doesn't work from the drivers side either than it is most likley the motor that is bad

A DC motor can fail a couple ways. One is the bearings seize and the armature can't rotate. In this case you'll likely hear some noise and as suggested earlier a slight drop in voltage as evidenced by dimming lights. Of course it could be a blown fuse upstream as well. The second way a DC motor fails is the windings burn and go open circuit and/or the brushes on the commutator go bad. Probably not fixable and better to replace entire motor.

If you don't have a test battery you could just probe for voltage at the motor connector. +12VDC and Ground applied to two wires for one direction and the voltages should be reversed for the other. If you have voltage then this points to an open circuit motor. If no voltage your mystery moves to wires, switches, and fuses. A common failure is breaking wires in the hinge area. The wires get flexed every door open/close so eventually break inside the insulation. A test for this would be to have someone depress the window switch and then try yanking the rubber boot with the wires to the door in question and at the drivers door. If wiggling gets a momentary burst then you know the broken wire is in that bundle. You'll need to go in a splice a piece of wire to repair the broken wire. Use shrink tubing and or electrical tape to re-insulate all your solder joints.

Posted
if it doesn't work from the drivers side either than it is most likley the motor that is bad

A DC motor can fail a couple ways. One is the bearings seize and the armature can't rotate. In this case you'll likely hear some noise and as suggested earlier a slight drop in voltage as evidenced by dimming lights. Of course it could be a blown fuse upstream as well. The second way a DC motor fails is the windings burn and go open circuit and/or the brushes on the commutator go bad. Probably not fixable and better to replace entire motor.

If you don't have a test battery you could just probe for voltage at the motor connector. +12VDC and Ground applied to two wires for one direction and the voltages should be reversed for the other. If you have voltage then this points to an open circuit motor. If no voltage your mystery moves to wires, switches, and fuses. A common failure is breaking wires in the hinge area. The wires get flexed every door open/close so eventually break inside the insulation. A test for this would be to have someone depress the window switch and then try yanking the rubber boot with the wires to the door in question and at the drivers door. If wiggling gets a momentary burst then you know the broken wire is in that bundle. You'll need to go in a splice a piece of wire to repair the broken wire. Use shrink tubing and or electrical tape to re-insulate all your solder joints.

I had the same problem with my ES. The dealer dealer said that that ESs come with a defect and when you do not use the window for a long time, it jams itself along the ruber around the window. He told me to apply manual pressure to the window while holding the switch down. This fixed the problem after a little struggle. However, my windows jammed again the next summer. I have not bothered to try to fix it yet as I hardly roll my windows down.

Posted

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hi i am having a similar problem, however mine is worse, i am slowly losing all my windows, first it was the front passenger, then all but the drivers window, then all windows plus the the gas door, now its all including the sunroof, and finally today the power locks are dead...i did get under neath

near the inside fuses, and reset the breakers, which did bring my gas door back to life, but it is very strange, now i did notice that one corner of sunroof leaks now, so perhaps there is some crazy short going on, or not...all fuses seem to be okay...i know this isnt a motor issue, its a circuit issue...

does anyone have any ideas where this may have gotten wet? i do have a 1992, and i am sooooo ready for like a 98 or so, so maybe its time...this one has served me well, 300,000+ miles, but some speakers are dead, the seats suck, i am seeing a part of my paint starting peel...however i do need to get these windows up...

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