AC blowing heat on all settings (W208)
Thread Starter
Member
Joined: Jun 2005
Posts: 86
Likes: 0
From: Miami, FL
2000 CLK 430 Coupe
AC blowing heat on all settings (W208)
Hi all,
I've been searching for a solution for this, but am not sure I have found a good starting point for troubleshooting. I would appreciate your input.
The air conditioner in my 2000 CLK 430 is blowing hot air, regardless of fan speed, temp setting, and "EC" on or off. And I do mean hot air--not outside temperature, but heated (correction: appears to be uncooled, not necessarily heated). I hear a slight change in the sound of the fan when pressing the EC button, but no apparent drop in RPM and no obvious change in sound under the hood. This happened one evening, after months of trouble free cooling.
Another symptom I noticed over the last few months is that there is occasionally a loud thud when I switch between recirculate and outside air. Also, a few weeks ago, the AC button on the driver side stopped working; in fact, it doesn't seem to move at all when pressing it. The passenger side one works and is able to engage "auto" mode.
The blower resistor, compressor, drier, and refrigerant were replaced 6 months ago. The most recent services have been an oil change, transmission fluid and filter change, and fuel filter change. The car has just over 80,000 miles.
Any insight you can provide would be most appreciated.
Thanks,
e harmon
I've been searching for a solution for this, but am not sure I have found a good starting point for troubleshooting. I would appreciate your input.
The air conditioner in my 2000 CLK 430 is blowing hot air, regardless of fan speed, temp setting, and "EC" on or off. And I do mean hot air--not outside temperature, but heated (correction: appears to be uncooled, not necessarily heated). I hear a slight change in the sound of the fan when pressing the EC button, but no apparent drop in RPM and no obvious change in sound under the hood. This happened one evening, after months of trouble free cooling.
Another symptom I noticed over the last few months is that there is occasionally a loud thud when I switch between recirculate and outside air. Also, a few weeks ago, the AC button on the driver side stopped working; in fact, it doesn't seem to move at all when pressing it. The passenger side one works and is able to engage "auto" mode.
The blower resistor, compressor, drier, and refrigerant were replaced 6 months ago. The most recent services have been an oil change, transmission fluid and filter change, and fuel filter change. The car has just over 80,000 miles.
Any insight you can provide would be most appreciated.
Thanks,
e harmon
Last edited by e harmon; Jun 7, 2010 at 11:28 PM. Reason: realized that air was not being heated
Thread Starter
Member
Joined: Jun 2005
Posts: 86
Likes: 0
From: Miami, FL
2000 CLK 430 Coupe
Some more info: the Auto light does not go out when I change the fan speed manually.
Also go these readings by using the REST button:
1: 86
2: 82 (79 with engine off)
3: 90
4: 89
5: 88
6: 174 (possibly climbing; 135 with engine off)
7: 0
8: 93
9: 0
10: 0.9
20: 0
21: 0.6
22: 0
23: 100
24: 14.3 (12.3 with engine off)
40: 8
41: 5
42: 200
43: 14
Thanks and regards,
e harmon
Also go these readings by using the REST button:
1: 86
2: 82 (79 with engine off)
3: 90
4: 89
5: 88
6: 174 (possibly climbing; 135 with engine off)
7: 0
8: 93
9: 0
10: 0.9
20: 0
21: 0.6
22: 0
23: 100
24: 14.3 (12.3 with engine off)
40: 8
41: 5
42: 200
43: 14
Thanks and regards,
e harmon
MBWorld Fanatic!
Joined: Apr 2005
Posts: 3,784
Likes: 84
From: SCV SoCal
2002 CLK430
Answered in the W208 section. The Freon pressure is zero (empty? compressor not running?), and the heater cores are hotter than the cabin air ( usually a sticky duovalve). Those are two separate issues.
