rear window defroster problem

[timmyj51]

When I hit the rear window defroster switch it lights up and then starts to
blink after a few seconds. According to the owners manual
this means the relay senses there's not enough power to
operate the defroster and so turns itself off. Thought maybe
not enough power in the battery but it tests strong and the
switch continues to blink even after I've driven for a while when
the battery should be charged. My mechanic thinks its a bad
connection and wants to rip into the roof support to get to the
defroster wiring but before I
let him do this want to know if anyone else has had this
problem. Could it just be the defroster relay? The car's got
a brand x, not an MB, battery. Could this also be the problem?

[joboo]

i have the same problem and I also would like an answer...anyone??

[timmyj51]

Was searching the net for info on this problem and came
across a guy who had the same problem with a '96
S420. He was sure it was either the N10 Combination Relay
in the engine bay or the k13/1 relay (which is supposed to be the defroster relay) in the trunk. When I
get time will have a mechanic check if these would be causing the
problem in a C220. Meanwhile, does anyone have any more
information on
these relays?

[timmyj51]

Problem was the combination (N10) relay.

[stox]

Originally posted by timmyj51
Problem was the combination (N10) relay.

That does seem to be a repeating theme lately.

[timmyj51]

OK, I had a mechanic test the combo relay and he said that's
the problem with the defroster. A day later I reached to turn on my
windshield wiper and noticed it was off in the high position!
It runs at only the regular speed in all the other positions,
even off, and only turns off on the high setting! Did a search and one
post seemed to say if you unplug the wiper motor you have to reset the wiper speeds when you plug the motor back in or something to that effect when you replace the combo relay. Is this so? Does
anyone have any information on doing this? Have a feeling
the mechanic unplugged the wiper motor when he
was testing the relay and didn't do anything to reset it. The
wiper was working perfectly up til then.