The passenger window switch on my 1995 SC300 began to fail intermittently. The part from the dealer costs $164.74 (at the very least). As such, I decided to try to fix it first. This is a write up of what I did, both my success and failure.

DISCLAIMER: The master switch is an expensive and delicate part. Evaluate your mechanical and electrical skills honestly, and take this project on at your own risk. I make no guarantee of success.

1) Remove the master switch by gently by prying up the front and then sliding the entire unit forward.



2) Here's a view from underneath. The window switch module is easily removed by unscrewing the three silver colored screws.



3) The window switch module has four switches that must be removed before the two halves of the module can be separated.



4) This shows me prying the easy one off with a small screwdriver.



5) This image shows where it all went wrong. The driver's side window switch is the hardest to remove. It is difficult/impossible to see how it can be pried without x-ray vision. As you can see, I broke it. I hope this image will give others a better chance of getting it off without damaging it.




6) Here's the naked board.



7) The next step is to open up the failing swich. Each white window switch is made of two halves that click together. They would be easily separated if not for an annoying design that locks the LED to the top half of the switch.



8) I decided to unsolder the LED. In retrospect, I could have cut two furrows in the upper case to free the LED leads (see pic below).



9) Once the LED is freed. The halves of the switch are easily pried open with a small screwdriver. The image below reveals the carbon build up which was the cause of the bad connection. I gently cleaned and scraped all this black stuff off the metal rockers and contacts.



10) Before re-assembling the unit I decided to cut two furrows into the upper case to free the LED should I ever need to clean this switch again.



I managed to fix the driver's side switch that I broke (in step #5) with a combination of superglue and hot melt glue. I re-assembled the master switch, and re-installed it into the car. All switches work beautifully now.

I hope that the images provided here will give others a greater chance of success should they decide to take this fix on.
Good luck.

 

I don't know if I would rather do this or just try and find a used one to replace the whole thing. Thanks for the write up. Its the first one that I have seen for this.

 

I replaced my window regulator and switch and stilll the driver window doesnt work the only thing on the driver side switch that works is window lock and unlock/lock door button. the passenger works just fine but only from the passenger side. any ideas?

 

I appreciate the effort but I would have definitely bought a used part from the classifieds section. In fact, I might need one soon. My mirror switches no longer move and it's annoying now. I guess it's a good excuse to not let anyone drive my car

 

nice i myself also enjoy tearing stuff down. i would have put a blue led instead though

 

great writeup. once all the parts are impossible to find this will be part of a sticky.

 

I'd pick up a used on though to save some hassle lol but nice write up nonetheless.

 

great writeup!! nothing wrong with my switches but changing the LEDs to white. Your DIY helped tremendously, I somehow managed to not completely destroy my Auto switch. If you can manage to lift one side out, try prying the other side out from underneath and popping it up..might help.

Thanks again!

 

the hardest part is taking off the window buttons.. thanks for the write up

 

Thanks much for the great instructions and images.

This is why the clublexus is the best forum for our beloved SC's

my auto switch came off rather easily, due in part to the fact the two center clips seem to already be broken.

I deduced this because the window goes down, not up, as the switch cover cannot engage the down position.

I disassembled as directed with very similar problems on switch removal, but pried up one side as a thread suggested... It worked better I think.

cut the LED plastic with swiss army knife scissors (worked rather well) and did the cleaning.

Looks like I need to replace the switch just the same, as those pins are broken...

I did consider anchoring a needle into the switch so I'll keep you posted if I try that.

Finally, found a replacement switch at the local wrecking yard.

Lucky, around $50!

Steve

 

Thank you for your posting. Your write up and images help remove the uncertainties that I had when I first attempted to pop the rocker covers on the switches. The biggest hurdle was removing the AUTO rocker cover. Once that was done the rest was straight forward.

Here are my tips:

1) To remove the AUTO rocker cover, avoid prying the thin outer cover. Instead depress the rocker on the AUTO labeled end so that the opposite end is raised up. Then peer into this opposite end and try to wedge a small screw driver between one of the flange clips (these are thicker with a retaining hole) and the switch body and pry the rocker cover off.

2) Cutting the furrows on the plastic retainer for the LED was simple with an EXacto knife. Then just bend the LED out of the way so that you can separate the switch.

3) I directed a spray of electrical contact cleaner on the contact surfaces to remove the grime built up on them. Before reassembling the switch, I smeared on a minute amount of white silicon grease onto the contact surfaces to prevent oxidation and to allow for a smoother mechanical action of the switch. One doesn't need to worry about the grease interfering with the electrical conduction as explained in the inset "How Contact Lubricants Work" in the following web page: http://machinedesign.com/article/lub...-switches-1025

My window switches are working great now! I don't have the intermittent switch problem any longer. The total cost was $6 for the electrical contact cleaner.

Thanks again for making this project relatively easy for me.

 

Thank you I have done similar to other manufactures of autos blind ( No instruction) This was Very good. should save me some wrench skipping.

 

I used a dental puck after 30 frustrating minutes and had the rocker button off in 30 seconds 🙃