I had a 280e with intermittent windows, and all the switches tested fine with the few mA of current from the meter. However the contacts were dirty enough that they had a large voltage drop across them with the relatively high current of the window motors.

I cleaned the switch contacts (this was a '77 and they were easily disassembled) with a product called Cramolin which is now called "De-Oxit" and it fixed all but one switch. I replaced that switch with a new one and it was fine.


Tim