W202 A/C strange - PeachParts Mercedes-Benz Forum

umut · #1 06-08-2007, 08:35 AM

Hi to all members,

Here comes my problem:
My recently bought 1994 C180 (1,8 liter M111) is equipped with manual air conditioning sysytem (Euro style one with dial knobs). And after cold-starting in morning the light on the "EC" button comes on (fan selector at "0" position) and stays on unless i manually turn it of. If i turn it off manually it turns itself on again after 4-5 seconds and i can hear the vacuum pump running in the trunk together with a vacuum element "squeaking" behind the glovebox. This wierd behaviour of the system continiues for 10 - 15 minutes. Then everything returns to normal ("EC" light goes out and only comes on when fan selector is set at least "1", Cooled and heated air available from all ducts/vents)

I know that if "EC" light is lit constantly, it indicates a low refigerant level but my A/C blows cold enough for me and rest of the system operates normally after first 10 - 15 minutes of driving.

I will apriciate all comments on the problem because it is starting to make me angry over the time and i do not want the local stealership touch my car before i have i clue about what is going on.

Thanks in advance
Umut
1994 C180 Polar White

rorypff · #2 06-09-2007, 04:45 AM

The EC switch is the econo switch for switching the aircon off - has nothing to due with low aircon gas. If your fan/blower rotary switch is in the O "off" position then the aircon will be switched off, as well the air flap will also be in the closed position. The funny noises you hear will be the air flaps modules working, maybe they are leaking also. Iam not sure why the vacuum pumpwold be running, possibly a leak there also.
regards

blackmercedes · #3 06-09-2007, 11:13 AM

Quote:

Originally Posted by rorypff

The EC switch is the econo switch for switching the aircon off - has nothing to due with low aircon gas.

On many of the MB A/C systems, the system will go into EC mode if there is a fault in the system, be it low pressure (protecting the compressor) or a sensor fault. If the EC engages on its own, it's a sure sign that the system is faulting somewhere.