gv1798

Hi,
I recently purchased a ML270CDI which had a couple of problems, most of which I have rectified with the exception of one - the Air Conditioner.
For some reason the air conditioning controller does not output the 12v to activate the compressor. The heating and other functions are fine
I have:
- activated the compressor by disconnecting the line and placing 12v directly on the input (and get cold air)
- replaced the pressure/temperature switch
- recently replaced the controller (AAC - 3 dial control unit).
- checked at the AAC for the sensor inputs and this appears to be fine.
- checked/cleared any error codes.
- checked the internet and read many threads, however still at a loss
- checked level of refrigerant (actually this was replaced)

Is there anything else I have missed that would stop the AAC from outputting the compressor activation signal? Does the new AAC have to be coded (variant coding) into the system? Any good advice would be greatly appreciated

- thanks

gv1798

Further to the info above, I have been able to use a more upmarket OBD reader that reads many more codes than the unit I have. I found error codes B1105 and B1204 stored. I cleared these codes however after starting the airconditioner, these codes returned.
Also tried to manually activate the compressor via the AAC via the OBD, however still no output, only the error codes.
The vehicle was manufactured in 2003
I am having trouble trying to find any detail on these codes. Has anyone had any experience or know of these particular code. I would really appreciate some help - thanks

BigCat

I also have the beginning of an a/c problem. the driver zone takes a while to cool, usually happens quicker at highway speed, than the ice cold passenger zone. Any ideas on possible causes?

Maj. Dundee

You are on the wrong forum. You must go to the W164 forum.