Help! AC Not Working!
Thread Starter
Newbie
Joined: Nov 2009
Posts: 7
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CLK550
Help! AC Not Working!
My blower motor was making a rattling sound for months. I knew the issue (from this forum) but didn't bother to fix it because it was just an annoyance and not a critical issue. I noticed the other day the blower would no longer push any more air on the "highest" setting (basically setting 4 and 5 were the same) so I figured the motor must be going. I ordered a replacement and installed it with no issues. Rattle was gone, but still no faster air on the highest setting. I thought this was odd, but not a big deal. Yesterday, the air got even slower, with setting 3 now the same as 4 and 5. Trying to cool off the car in 95+ degree heat with a max fan speed of 3 is tough, so I read up online and found out about the AC "reset" option where you hold down the recirculate and defrost buttons for 10 seconds. Figured the issue could be in the ECU (since the motor is brand new) I tried it. Now the AC motor will not turn on at all. No air, period. I tried resetting 3x, and it is still totally off. I have an appt next week at my repair shop to look at it, but it's hot out now and I need the car. Anyone have any ideas on how to fix it?? There's no error codes or check engine light, just no airflow at all.
MBWorld Fanatic!
Joined: Jan 2012
Posts: 1,043
Likes: 310
From: NYC
E63S
Yikes. Sorry to hear about your predicament. I have not heard about this issue before, but, have you tried disconnecting the battery to do a reset? Let us know how it goes when you figure this out. GL.
Senior Member
Joined: Apr 2010
Posts: 394
Likes: 156
2013 E63 P30, 2010 GL550
Agree. This sounds like a $40 replacement of the resistor module on the blower motor. It takes 30 minutes to swap out with basic tools like screwdrivers. If another resistor does not work, the next suspect is the motor itself. Not very expensive either. eBay items can be returned if needed. Low risk. Try it.
