Window Switch (slow/non-reliable windows) Repair (1 Viewer)

[Chris Wilcox]

A few years ago I tackled the window swith problem with no improvement. At that time it was a quick job except for adding the auto up mod! Disassemble, clean off the carbon with a light sanding, wipe with rubbing alcohol, then I made the mistake of putting dielectric grease in the contacts. It wasn't too long before the windows were inconsistent in their operation and over the months it became progressively worse to the point I had to disassemble again. The speed never really improved as it was always bad.

Recently I took it apart and found lots of black at the contacts and also the faces "burned" as one would expect from years of use. Unexpected was a bit of melting of plastic near the drivers up contacts. Things must have been warm at some point. Probably recently. I cleaned the contacts thoroughly with 320 grit sandpaper and/or red scotchbright until the black was gone.

I'm not an electrical engineer but I began researching how to prevent this flash and burned contacts and was directed at first to a RC snubber and then to a flyback diode. Studying the google content I tried my best to apply the arc suppression flyback diode to the circuits for the window motors. The schematic below shows what I believe represents a proper application of a flyback diode but like I said this isn't my forte and it might be wrong.

I had eight 1N4005 diodes in a bin. Soldering these in was a lengthy process but they did fit and everything went back together.

The window is now very fast, comparable to our 2009 sienna van actually in speed but a bit more grit in the window track by the sounds of it. All 4 windows move very nice except...

The drivers up doesn't work at all, down, auto up and auto down all work flawlessly. I'm hoping it is something to do with the melted plastic. Anyway I've taken the switch back out and will troubleshoot with a multimeter at first and then look at the schematic after that because my diode may interfere with the current sensing circuit possibly. Too late here to get into it any further.

If any electrical person can comment on the circuit it would be appreciated.

edit, checked the switch with a meter, no continuity drivers door 'up'. Will take it apart in the morning.

 

[Brandon98]

I suspect we may be in the same boat. I have a new aftermarket switch that I'll be closely examining and rigging jumpers to evaluate the motor and wiring to the motor. Too bad my son is out of town with his fancy HVAC multimeter that measures amp draw inductively...

 

[Chris Wilcox]

As suspected, once I built up the grey plastic bit that melted the 'up' operation works perfectly. Here's hoping for a bit of life span for this repair.

 

[SteelHunterFJ80]

Could you break down the process you did? I'm not at all electrically inclined but can you outline the steps. 2009 sienna speed sounds great!

 

[Burbot]

Oh yes please detail this repair. Make it for dummies if you can because it is so common. On drivers window if it's -10 DONT open the window! Or you'll be driving that way until it's good n warm. A bit more juice might help. The is also an issue of friction in the track esp on the drivers door. It pinches at the wiper because of loose trim fit.bit that's a separate issue

 

[Chris Wilcox]

Because I'm not sure the diodes are properly applied I won't want to make this too factual on that part. For the switch contacts however we can expand some.

0. Removal of the switch is easy, gently pry up on the front of the part in the armrest then remove the switch connector.
1. Remove the 3 screws holding the switch to the trim colored piece.
2. Pop off the square black with orange line switch off button.
3. Remove the 4 black screws holding the switch rockers to the base. For this you need to stay level as you will lose two little springs and 8 or so metal bits that make the switch contact. A camera here is a good idea for memory.
4. Take all the loose pieces off and place them in order in a clean area.
4a. Clean the contact tips of the loose rockers removed. for this I used red scotch-brite and rubbing alcohol with a Q-tip.
4b. Clean around the switch contacts in the base with alcohol and Q-tips.
4c. Clean the black off all the contacts in the base with red-scotch-brite. On mine each switch rocker had one black contact and one copper. The black one looked like is was originally silver, at least that is the color it was when I was done cleaning. Again use q-tip to remove any particles or mess.
4d. For the drivers door the switch is different. The contacts are flipped and on long metal bars that bend. These were very black on mine. I used 320 grit paper (because it is the finest I had on-hand, an expert may have a better recommendation) and folded it in half and was creative. Put the paper between the contacts and use light pressure on the grey switch piece to press the contacts together while you pull-push the 320 back and forth to clean them. Inspect with magnifying glass to track progress. If one side cleans fully before the other, put one layer of 320 in so you don't wear the clean side too much. Do this on all 4 contact sets and clean up with alcohol and paper towel because it is then and gets into the contact area better than Q-tip. This is the cleaning that restores the function but the diodes are intended to reduce the future arcing and damage to the tips.

Steps 5-9 apply only to installing diodes.
5. Flip over the switch and pry off the clear plastic housing. Use a small screwdriver and be gentle.
6. Remove the small Phillips screw holding the connector housing, then slip off the yellowish connector housing.
7. Install 1N4005 diodes as per the picture and schematic above, 8 total, but be aware that this schematic ic not vetted by an expert. You need to gently bend (without a permanent bend) some of the metal leads that go over to the connector removed in step 6 to gain access for soldering.
8. When installing the rear door diodes they need to be tucked down as much as possible. Even still I had to shave a tiny bit off the back of the yellowish connector so they weren't squished when I put the little Phillips screw back in. Minimal material as in 20 thou from the center section only where Toyota beefed it up a bit for the screw boss.
9. re-install the connector housing which can be tricky to get all the pins lined up bit use a long thin screwdriver to aim them as needed.

10. Install remainder reverse order. and test. If you have issues you can test with a multimeter. I had some melted gray plastic which interfered with the function.

I built up by plastic by epoxying a thin piece of old circuit board material because it will take the heat.

This doesn't guarantee it will work in the winter because it is 25 °C here now and I can't test the cold!

 

[musthave]

Well done, incredibly useful write up!

 

[BigAxeJack]

I agree with the above statement. Nice research and write-up. As time passes could you please update regarding the long term efficacy of the diode mod?

 

[Chris Wilcox]

I compared the speed to the van, it isn't quite as fast but compared to what I was working with it was worth the effort.

 

[Burbot]

Thanks very much. A parts list with diode types in the future might be helpful. My son wants pwr windows in his 86 bj70. I scavenged everything from a lj78 now have every thing in a box. I'll clean up his as practice,then do mine.

 

[Dissent]

Nice writeup. I just cleaned my drivers switch and did the auto up diode mod Sunday. They're a bit faster but nothing to write home about. This diode mod sounds interesting.