Window Switch current arc damage

[the_hairy_baboon]

how do I future prevent window switch current arc damage?

I followed the ozvolvo (https://ozvolvo.org/archive/) article (Window Switch Refurbishing.pdf) and sanded off the contacts. Two helpful items attached.
1. Certain versions of the switches do not pop out of their housings like the article suggests. Mine have little clips on either long side. A small flathead prying will allow them to pop out.
2. Certain versions of the switches do not disassemble as the article suggests. Mine only release the switch up top. The top of the hinge holders is kind of fragile - I've had best luck from prying over near the tabs then working over to the hinge till it pops free. Repeat on the other side. Assembly is reverse of installation (i.e. a bit of screwdriver usage is needed to reassemble)
3. To make sure you reassemble correctly (make sure the jankier switches stay for 2nd row) I'd advise taping the switches with location and direction so reassembly can be coordinated.

But fundamentally the issue is that these switches have to carry 12V window motor power, not just signals. Does anyone have a method to make the motors controlled by something else to prevent switch corrosion?

From what I have researched, for each window I could install a set of 2x SPDT relays. Both sit normally providing ground to the motor (one to each of the motor wires). Then if a window switch sets that side high, it'll use the relay to send 12V to that side of the motor which will cause a directional spin. The window switches self protect against both being high, and at rest both sending ground is safer than both sending 12V (in case of resistance causing different 12V values). I could hijack the 4 pin for +12V power, and the 3/5 pins for ground.

All in all, that would avoid the switches building up terminal damage (and pass it to the relays). Is that really any better? Should something inline actually go to transistors? Given this is likely the first time they've been cleaned, am I overthinking it and just having sanded contactors should be good for ages (or just buy new switches over developing/installing a new method)?

 

[cleanflametrap]

... Given this is likely the first time they've been cleaned, am I overthinking it and just having sanded contactors should be good for ages (or just buy new switches over developing/installing a new method)?

I'm thinking you'll be set for another 20 years with a good cleaning, though I cringe at the verb "sanded" imagining loose abrasive embedding in the silver. There are tools for cleaning contacts made of thin rough metal (contact burnishers) I've used, but as to how long the fix lasts, I can say it has been at least 15-20 years * since I've last pulled an intermittent window switch. Probably other factors, but a solid state relay fix might fall into the overkill category. "not that there's anything wrong with that"

*Now that I've said that, next time it starts raining I won't be able to raise the window.

 

[the_hairy_baboon]

*Now that I've said that, next time it starts raining I won't be able to raise the window.

Exactly - the car has AC but not retrofitted from an EPA illegal format (whatever the original was) so windows down is my AC, but rain hits fast and hard here.

Ideally I'd figure out something not terribly expensive that basically sits between motor and wire harness that goes to the motor, steals power locally from the $4 on the switch, and I make and install as needed (i.e. as a given window becomes a pain, add it). Chances are, even with crappy contacts, you'd have enough voltage/current to fire a relay/transistor, so you wouldn't have to clean them at all.

 

[dl242gt]

I used to use the burnishing file that Are mentioned above. Cleans the contacts in the switches very well without removing too much metal. They were small strips of slightly rough metal to drag between contacts to clean them.