84 325e (real early 6-hole 3 series, 2/84 build) car is theft recovery. lots of damage in and around steering column/dash. above the (hole for) the radio are three buttons, l-r: hazard, rear window defogger, window/sunroof button circuit reset. SHOULD the rear window defogger light up with it (a) pushed "on" or (b) with the headlights on. the defogger does not work, but I suspect the switch is the issue...I replaced original with one from the junkyard to no effect. perhaps another one. but is there a light to indicate that the switch itself seems to be working?