PeachParts Mercedes-Benz Forum - View Single Post - cleaning the window switch restored rear window

jay_bob · #7 05-23-2016, 11:01 AM

Please don't abrade electrical contacts to clean them!!!

The contacts in these old models were built nice and stout, with a solid copper core with silver plating. However if you scrape the plating off, it will work great for a while, but then as the copper oxidizes, the contact resistance goes way up. This gets the contact overheated, and then it fails permanently.

Please, instead of abrasion, try Tarn-x on a q-tip. If you can't find it, use silver polish and carefully flush out the residue.

It is a testament to the design of these older models that you can actually take a switch apart and maintain it. The seat and window motors draw around a dozen amps or so and the switch had to be stout to handle the load.

On the newer models, where you are switching a low level (milliamperes) signal to a digital module, the contacts will last forever, and it is normally the internal spring or detent that fails. So they made the switches throw aways.

We use silver plated copper bars in the equipment I work with. The bars carry thousands of amps, and I have seen some spectacular failures, where someone used sandpaper to "clean" the bus contact pads.