1992 ls400 POWER WINDOW SCREAMS LIKE A BANSHEE!!

[threepwood]

Suddenly and for no apparent reason the passenger side power window screams like a banshee going up and down.  I have removed the regulator, removed the gear cover, greased everything insight with PB blaster and wheel bearing grease with no change in sound level.  Any ideas?  My thought is as a last resort I would try to exchange the motor gear assembly with one from the rear window which is never used.  Don't know if that is possible.  Really curious if anyone knows what stops the window when its fully up or down ( limit switch? torque switch?).  Any suggestions would be appreciated.

[paulo57509]

The four window motors are different part numbers.  However, Rock Auto catalong shows that the motors are interchangeable.

The motor and regulator are available in the aftermarket.  I would avoid Cardone if at all possible.

By application:

https://www.rockauto.com/en/catalog/lexus,1992,ls400,4.0l+v8,1187478,interior,window+motor,1516

By motor part number:

https://www.rockauto.com/en/partsearch/?partnum=+85710-50010

The limit "switch" on my '98 appears to be current sensing; each door has it's own ECU.  When the ECU senses higher current when the window reaches it's open/close limit, the current rises.  The ECU senses this rise and shuts off power to the motor.  At least it appears this is the way it works based on the way it's tested.  I have no idea how earlier models are designed.

[threepwood]

Many thanks for your quick response.  I will try exchanging with the back window and see what happens.  Will let you know.

[Volleypop]

I have had a similar problem with my drivers window after some soda got spilled down inside the window channel and I too have tried silicone grease in the window channels ( from Amazon ) but the one thing that seems to be most effective is regular cleaning using Rain-X Automotive Glass Cleaner ( without Rain-X in the formula  -$5 @Walmart ) and a microfiber cloth. This seems to be the best window cleaner out there and works for me every time when used on inside and outside. I do use some Rain-X water-proofing on the outside but the cleaner itself is what seems to fix the squealing problem most.

BTW I know this sounds crazy but researched this fix ahead of time and didn't believe it worked until I tried it myself. I suspect that maybe the soda contaminated or stiffened the little bristles lining the window channel but nothing seems to clean or remedy them if that's the root cause.

Edited August 25, 2023 by Volleypop
Additional info added

[threepwood]

That is my worry, that the noise may not be coming from the motor gear assembly.  I'll try it. thanks.

[threepwood]

Just thought I would update you on my final solution.  No amount of grease, penetrating oil, etc. anywhere on the door or gearbox could stop the noise.  So it is the motor.  Thanks to paulo57509 for the rockauto info as it told me I should exchange the motor gear assembly with the rear left door assembly and not the right as I had planned.  Bottom line, the noisy motor gear assembly is now installed in the rear left door that no one ever uses and the silent one from that door is now installed in the passenger side right and works quietly again.  One little quirk.  The leads on the motor from the back door were shorter than the leads on the original motor so i had to make a 6" jumper in order to make the connection.  No problem.  Thanks again to all for the help.

[paulo57509]

Glad you got it sorted.

After I posted I started wondering about the motor wiring.  I've seen what you have described - short/long wires or the connector is clocked (locating/locking tabs) are backwards.