W202 (1996 C220) Electrical Issues - PeachParts Mercedes-Benz Forum

tobybul · #1 10-30-2008, 12:37 PM

Rear Window Defroster and High Beam Flash

These 2 functions are not working on my C220 and am wondering if they are controlled by the same relay.

I'd like to open up the steearing column and chk the combo sw but i don't think thats the problem with the high beam flash function. My low and high beams work but not the flash function.

The rear defroster does not function. Howver the switch appears to work becasue the sw indicator light comes on when I try to switch it on.

Any ideas

mpolli · #2 10-30-2008, 04:23 PM

My guess is those 2 problems are not related. I would guess the flash problem is a bad stalk switch (I think there is a better name). There have been several threads about those switches going bad. Mine has been fine luckily although it always felt kind of cheap.

On the defroster, That draws a lot of current so even a partially bad connection will cause it to not work. If you can test the voltage at the window connections, both with them connected and also disconnected that will give you some info. For example if you get good voltage when they are disconnected but no voltage when they are connected then there is a bad connection or relay in the path from the battery to the window. On the other hand if you get good voltage when they are connected then the problem is the window element or connections immediately to it. And if you never get any voltage then the relay is not getting the signal to turn on or there is a completely bad connection somewhere.

timmyj51 · #3 10-30-2008, 07:48 PM

Bad combination relay is almost certainly causing the rear defroster problem,
as it was with my '95 C220. Certainly check that before you rip up your defroster
connectors. The relay may also be causing your flash problem. Think,
but not sure, that function is controled by the same relay.

mpolli · #4 10-30-2008, 11:34 PM

I bet timmyj51 is right. I searched on "C220 defrost" and found lots of threads. They didn't seem to mention the high beams though. But it could be related. Seems a little strange though since you say the high beams do work, just not the flash position. I still go with the switch on that one.

tobybul · #5 10-31-2008, 08:51 AM

Thanks for the opinions, Everyone. If only the airbag does not need to be removed to get to the combo switch, I would have checked it by now.

I have this impression that its a PIA to work on although I have never tried it. I fear that I might deploy the bag and that the assembly may not work after I put it back together. Maybe - I better stop thinking too much about it

tobybul · #6 11-01-2008, 09:45 PM

Read my Haynes and it said to chk/feel the relay while the defroster sw is turned on/off. If the relay clicks then the relay should be ok and the problem may be the wiring going to the defroster.

Well, my relay does click so now I gotta look elsewhere.

And, I don't think the headlight flash is controlled by a relay. If so, then it must be the combo sw.