Air con pressure switch location

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m2mb

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Sep 4, 2011
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Earth (blue pale dot)
Car
E220 CDI 2008, E220d 2019
Hi everyone,
Sooo guys i am having an air conditioner issue with the 2008 Eclass. I am not a mechanic, some pointers by you kind people would be appreciated before i have it professionally checked. Compressor was replaced couple of years ago with an original one, condeser years before. Problem now is Interminent operation. Sometimes a.c. works, sometimes not. When it kicks in then its fine blowing icy cold air, so i guess no gas leak issue?. I also get hot or cold air (when it is working) from any side as desired so this i gues tells me duo valve is ok?
So next suspects would be pressure sensor_switch or the compressor clutch or any other electronic component_ connection?
Where is the pressure sensor located btw?
In most occasions so far, the a.c starts to operate fine BUT only after a trip, with a restart of the engine (during motorway trip not operating). The dash light is not blinking but steady red as it should be! No funny noises either.
When its dead all vents blow ambient temperature air, or hot if temperature cranked up.
Other Ideas please?
 
Just found out the compressor has no clutch?
Resolving this will be interesting
 
The compressor has no clutch, it is a variable displacement compressor so the pulley, and its centre plate, will always be turning with the engine.

It is also worth noting that the pressure threshold to trigger the flashing red light on the dash A/C button is some time after the pressure has got low enough to stop the aircon working, i.e. solid red light does not equal refrigerant pressure is fine. The pressure sensor is on the passenger side inner wing, in the engine bay, headlight side of the wing.

When my '09 E220 had the same symptoms, intermittent operation but icy cold when working, it turned out to be the electrical demand switch on the compressor - not sold separately, and only a new compressor solved.

I would be getting yours to a Kwik-Fit/ATS and getting it re-gassed to start with, unless you have a way to measure the refrigerant pressure yourself (gauges, iCarsoft etc.). On my car, 3 Bar pressure (engine running) is low enough to stop the aircon working, but not low enough to trigger the flashing red light.

Martin.
 
Thanks for the info. I hope its not the compressor again. I will get a cheaper one this time if it is!!!
 

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