Air con electrical fault

[yillib]

Hi,
I have a 2002 E220 CDI W210, the electromagnetic clutch on the air con compressor stopped working, I have bought a new compressor and receiver/dryer which I am about to fit, on checking the supply voltage to the compressor I am getting 8.8volts regardless of whether the air con is on or off.
I presume it should be 0v when off and 12v when on, can anyone help me with this as I do not want to connect the supply to the compressor until I am sure it is right. Cheers.

 

[Lambrettalad]

It's 12 volts approx at the battery ,this can be stepped up or down by the cars electric brains ,

unless their is a fault in the feed,and it's live it will display the voltage that the brain gives it ,which may or not be 12 volts

eg the phone module on my SLK runs on 7 volts to fire it up ,no seven volts? it will not switch the visseoo on

good luck

 

[yillib]

Thanks Lambrettalad,
I also have an EPC viit workshop message which comes on now and again which may be connected to the same fault, I have got the WIS program on my laptop but find the wiring diagram too confusing to follow,looks like I will have to take it to the dealer to get the codes read.