W124 E220 Air conditioning

[Bert Lad]

Hi everybody ,

After servicing the Wiper Motor and the heater blower motor I noticed that my airconidtioning did not function . I checked and found that the compressor does not switch on . As per a friends advice , I shorted the leads on a the sensor switch(mounted on refrigerant bottle (with window) and found that this switches on the compressor but it does not get cool. The pipe leading to condensor does not get hot as it normaly should . My question is :

1 - I suspect that there is no referigerant - hence switch open circuit - I suppose to protect the compressor .Can someone please confirm that this is true ? or is it that the sensor switch has gone faulty

2 - Is it possible that a by servicing the heater blower motor, there could be something that could have gone wrong here - I mean sudden loss of refrigerant?

3 - If there is a leak what is the best method to detect it ?


Thanks in advance
Bert

 

[Richard Moakes]

1 - I suspect that there is no referigerant - hence switch open circuit - I suppose to protect the compressor .Can someone please confirm that this is true ? or is it that the sensor switch has gone faulty Bert

Correct, most likely your refrigerant has leaked, the switch is there to protect the compressor.

2 - Is it possible that a by servicing the heater blower motor, there could be something that could have gone wrong here - I mean sudden loss of refrigerant?Bert

Most unlikely, the gas nearly always leaks out over a period of time due to very small leaks and porosity of the hoses. However if this has suddenly happened, then start looking for damage to the compressor or condenser.

Although I do wonder how invasive was changing the blower motor? Did you have to disturb the main air box and the evaporator core?

3 - If there is a leak what is the best method to detect it ?Bert

You need someone to perform the following tests :

1). Vacuum test, does it hold a decent vacuum (basic leak check)
2). Pressure test with oxygen free nitrogen, and possibly a small amout of R22, then use a halogen detector to 'sniff' all hoses, joints, compressor, condenser for leaking gas.
3). If no major leak found, then recharge with refrigerant and add uv die to the oil. Wait until it has gone again, and then use a UV light and the yellow glasses to search for any areas on pipework, evaporator drain hose, compressor, condenser etc...

Find a good A/C man, not a dealership, and he should do all of the previous as a matter of course.

Good Luck,

Richard

 

[Keith]

did it work before you serviced blower?

Bert
what was the status before your foray into the blower?

having done my blower recently i cant see any connection to the functioning of the a/c circuit unless you deliberately tried to damage the evaporator and even then that would be difficult from the blower box.

Was A/C working AOK before ?

Is the blower working AOK full strength since you serviced it?

The only connection I can see between the two is if the blower isnt doing its job (eg you installed it wrong way around - yes its possible!) and isnt pushing enough air across the evap core so the evap temp sensor is cutting the compressor. Far fetched but I'm blowed if I can think of another link.

Keith

 

[twomercs]

The air con on my CLK packed up a few months ago. Mobile chap called around and replaced refrigerant and pumped up - £60 and been fine since, apparently there is a safety cut out switch on the compressor when pressure gets too low and latest eco-friendly fluid does not last as long as the old stuff they used to use - advised to have changed and pumped up again every 3-4 years.

 

[Bert Lad]

Dear all

Many thanks for you inputs - I am not sure if AC was working before my foray into the heater blower. Considering all , I have booked the car in with a AC specialist and lets see what he comes up with !

Thank you
Bert

 

[turnipsock]

The sensor switch you shorted works on pressure. If the system has no pressure...

It's possible you damaged the condensor somehow, when you were playing with the wiper motor.

Call an air con guy, they can repressurise your system and put in some dye so that if it has a leak, they can see where it is.

 

[Copiertech]

you can get a Ultra violet led keyring torch from maplins for about 3 or 4 quid, if earlier in your cars life its had a aircon recharge theres a good chance it might have had uv dye added, in the dark shine the uv torch around all the aircon components and see if anything glows.