Master Window Switch Problems 1990 Lexus Ls400

[amayes]

The window switch for the front driver side does not work anymore. All the other switches on the master switch work just fine and all windows roll up and down without a problem. I read another thread where it mentioned something about spraying PB Plaster? on the screws or contacts - something to that effect. I'd like to know if anyone has tried this and whether or not it solved the problem. That's a pretty expensive part and if I can avoid fattening up someone's pocket, that would make my day.

[TexasLexus94]

I'm a big advocate of PB Blaster. Simply take a flat screwdriver, and pop the controller out of its nest. Disconnect the electrical connector. Take the controller into the kitchen. No beer, send the kids and the old lady outside. Don't drop it, you will lose the springs. Remove the wood trim and the cover with the switches. You have exposed the electrical contacts that the switches control. The contacts are old and worn, like me. Spray a nice coat of PB all over the assembly. Wait a while, and then reassemble the unit.

Your problem will be solved. Guaranteed. Did it 5 years ago on my 1994. No problems since.

Best of luck.

[amayes]

I'm a big advocate of PB Blaster. Simply take a flat screwdriver, and pop the controller out of its nest. Disconnect the electrical connector. Take the controller into the kitchen. No beer, send the kids and the old lady outside. Don't drop it, you will lose the springs. Remove the wood trim and the cover with the switches. You have exposed the electrical contacts that the switches control. The contacts are old and worn, like me. Spray a nice coat of PB all over the assembly. Wait a while, and then reassemble the unit.

Your problem will be solved. Guaranteed. Did it 5 years ago on my 1994. No problems since.

Best of luck.

Well, I tried it. Bought the PB Blaster; disassembled the unit. Sprayed the electrical contacts and reassembled. Unfortunately, the driver side window still does not work. What next, new Master Window Switch?

[Lexusfreak]

Well, I tried it. Bought the PB Blaster; disassembled the unit. Sprayed the electrical contacts and reassembled. Unfortunately, the driver side window still does not work. What next, new Master Window Switch?

Get a price from your Lexus dealer for a new one (if they still can get them?)......but before purchasing, check auto wreckers & E-bay.

[curiousB]

well maybe the problem isn't the switch? Can you use jumper wires and short across the switch to see if that moves window? How about unplugging wires to windo motor and applying 12 vdc to it to see if motor is OK. Reverse polarity to go up or down. No point buying a switch if you're not sure that is the problem.

[MAD1964]

I have a 1990 LS400 Lexus. The rear right window goes down but not up. I took the panel out and verified the switch is working fine (took the switch out and tested with the rear left window and worked fine.) I reconnected the “window switch” and disconnected the “motor switch” to measure the voltage. Turned the key to ON position and I pressed the “”window switch” down (to lower the window) in which the meter measured 12v. But when I pressed the “window switch” up (to bring the window up) the meter did not measure any voltage (which explains why the window does not go up). Any clue what could be the problem and how to fix it?

[VBdenny]

If you have juice, then it just about has to be bad wire connection at some point.