2011 GLK-350 Heater (blower) intermittent operation
 

Last night, I was out in town and the heater worked fine (blower, specifically). It was about 32F/0c out. I stopped and shut the car off but left in ACC while I talked to a friend for about 10mins. Started the engine to leave and noticed I had no blower operation; the control panel responded to all inputs, but no forced air. Drove around trying to figure out what was happening, and was unsuccessful. Stopped at the store but stayed in the car. Shut it off, removed key, armed/disarmed keyless alarm, opened/closed door, restarted engine and like magic, the fan was again working. No more issues the rest of the evening.

Fast-forward to this morning, the wife and I were running some errands (33f/0-1c).. Started the car, and turned the heat on; worked as expected. Stopped at our first stop and went in. Came out, started the car, no blower.. Drove to 2nd stop, shut it off. Performed same function as last night, and the blower started as expected upon engine restart. Shut it off, went on into the store. Came out about an hour later, started the car, NO blower.. Tried the aforementioned sequence again, to no avail this time.
Drove home in the cold rain, no defrost or heat (aside from the heated seats and what little fresh-air forced heat we could get.
Got home, shut it off, opened/closed door, armed and waited about 1min. disarmed keyless, opened/closed door, started engine, BAM.. blower operation again..

I'm completely baffled with this. It's a 2011 with about 82k miles on the odometer. Any thoughts, suggestions, etc? Battery is semi-new, no slow starts or slow cranks, voltages test normal..

Thanks, in advance.

Update: I can't get it to come on at all, now. I suppose tomorrow I'll test for voltages at the fan.

GLK Blower problems
 

Did it turn out to be the Resistor?

Same problem in 2011 glk
 

I have the same problem in my 2011 GLK. The heater and AC work intermittently upon startup. I took car to dealer and they said I need a $1200 repair by replacing blower regulator and impeller blower. How did you get your heater fixed?
Thanks for any info you may share.
Best regards,
Mac

https://www.fcpeuro.com/products/mer...tor-2128200708

10 minute job!

More info on intermittent heater/AC motor
 

Thanks very much for your quick reply. I assume your answer is the blower motor needs to be replaced. The dealer recommended impeller motor ($468.16) and blower regulator ($519.80) with labor ($185.00) for a total of $1,172.96. Did you buy the blower motor in the link above and replace it yourself or hire someone else to make the repair?

I did it. I don't remember replacing the regulator, only the motor. IIRC, it was like 1 or 2 screws holding it in. was pretty easy. I 'think' it was a torx screw, T20? you do kinda have to stand on your head in the pass floorboard to see it, but it was still pretty quickly completed.

EDIT:
One screw. Removve the screw, and the blower motor will swing down from one side, and hang in place.. unplug it, then remove it from the hanger (lift it off). Hang new one, reconnect wiring, test function. if it spins with fan selected, turn off ignition, swing it up into place, reinstall screw, done.

Repair heater blower
 

Thanks. Great reply with very useful information. I'll try it even if I have to stand on my head! Better than $1200 to dealer!
Mac

Had the same issue in my 2013 GLK350. The fan comes out quite differently, but the original fault was that it was full of carbon dust from the motor brushes wearing down. Cleaned it, put it back in and it worked for a year. Happened again, and I found that the commutator was then coated with carbon deposit. I guess the brushes are softer as they wear down. I carefully spun the motor core against a tiny screwdriver to chip off the buildup, then used a knife point to ensure no connection between segments of the commutator. Put it back together, and it is currently working fine in much sub freezing weather. I'm betting on eventually replacing it, but this saves the cash outlay for now. :)

Here's a sample visual of a commutator and brushes in an electric motor from wikipedia....

https://en.m.wikipedia.org/wiki/Comm...ric)#:~:text=A commutator is a rotary,rotating armature of the machine.

Note: You can't change the brushes any more as they are crimped and soldered in place (at least in my original equipment).

Hope this helps.

I did that, too, but mine didn't last very long, so I jsut replaced it.

Thanks KanataSteve. I haven’t started the work yet, but when I do, I will certainly look at any problems with buildup in the fan and/or commutator. The problem started this past summer with AC. It worked most of the time, but occasionally, on a short trip after stopping and parking for a few minutes, when I restarted the engine, the AC wouldn’t work. I turned the system off and drove for a few minutes. Then, when I turned the AC back on, it worked. Recently, this winter, the heater stopped working. Again, after the car sat in the garage, it would start and run. No problem with stopping and restarting until yesterday. It would not restart after a short visit to a store. Very strange, and I hope a new blower will fix it.
Thanks very much for your helpful reply.
Best regards,
Mac

Regarding the AC, was it also the blower, or was it working and AC not?
I had to replace the control valve/solenoid in the AC compressor. I will say, that is not a job for the casual DIYer. I did it on mine, and it was about 6-8hrs trying to just get the compressor out of the engine bay. it's in the dumbest place ever.
But the valve was about $100, and the compressor (back then was about 800. Labor was 15-1600 IIRC.

AC always worked if cool air is the measure of working. When the fan was working, the air in the vents was cold.

I replaced this on my 2013 GLK about a year ago. I had some noise in my blower. Works like a charm. Took about an hour to do, because I was having trouble getting the new blower in the right spot. Ended up removing some screws around the glove box near the door, to shift the plastic a little so I could get the blower in all the way.

Blower is working much better now. I didn't replace any other components.

GeriatricGinger, I've ordered the part from fcpeuro and will let you know if it only took me 10 minutes to replace. So far, the panel covering the blower in the dash appears to have more than one Torx screw holding it, but I haven't done anything yet, so I'm not sure. Rather than stand on my head, I took a couple of photos with my phone camera and that is the basis of my observation. I really appreciate your sharing!!!!

Had to do the same, Mogulman. :)

GeriatricGinger, I have the motor and I've started the job. I have removed two screws and there is one more on the panel covering the blower. I am assuming it is behind the panel under the dash on the passenger side. There are three torx T20 screws holding the panel in place. I've removed 2 and want to know if this is correct. I assume after I remove the 3rd screw, the panel will come down revealing the blower. I assume that the one screw holding the blower in place will be revealed and when I remove that screw, the blower motor will swing down for me to replace. Is this correct or am I working in the wrong place. You didn't mention any panel, just the one screw holding the blower motor in place. I can send jpegs if it would help. I'll appreciate any advice you have time to offer on my GLK 350 blower problem.

I'm thinking I shouldn't have to say this, but there are Youtube videos for this. The blower is in a similar place as the cabin air filter. Search is your friend.

Yes, you are very correct. I looked on Youtube and found many videos but the blower motor in the 2011 is a little different from 2012 and 2015 in terms of how it is removed. There are three screws to remove the panel covering the "blower system", but the instructions on how to remove the blower are not consistent with what GeriatricGinger posted. I cannot find one torx screw that holds the panel with the blower motor. In the 2012 and 2015 videos, the mechanic showed how to remove the blower motor without removing any screws other than those covering the whole system under the dash. I am unable to find a 2011 video and it appears that every year, MB makes little changes, ha, that change how to approach this task without any room to work or see. Thanks for your reply and I'll continue looking for a video onthe 2011 version.

Sorry.. Didn't realize the 2011 was different. I didn't see any videos for 2010-2011. From the info I had, it looked like it might be the same.

There is a PDF linked here but still maybe not pertaining to 2011: https://mbworld.org/forums/e-class-w...ootwell-2.html

Thanks. I've been looking at videos for the past hour and nothing on the 2011 blower motor replacement. I just cannot see the same "geometry" in my vehicle that is displayed in either the 2012 or 2015 models. I'll keep looking and see what I can discover. It is very difficult for me to contort my body since I am 81, and my vision is very good so this is a problem. I may need to get some "younger' help! Thanks for your interest.

Oh yeah.. I have a fusion in my lower back. That was the hardest part. lying on the door frame trying to reach in there almost killed me.