ahm09

I have a W220 (S320 2001) that has front and rear A/C controls.It has the following symptoms regarding A/C:

• When I Turn on the front A/C only, it keeps blowing hot air all the time
• If I turn on the rear A/C in Addition to the front one and wait for about 5-10 seconds the cooling starts working normally at the front vents
• The rear centre left vent blow cool air, but the rear centre right vent blows hot air

when I used a scanner to I got the error shown in the attached image.(Duo Valve)

After sending it to the garage I deal with normally, he said that the A/C compressor is failing and said that the Due valve is not causing the issue.
He also refused to replace the Duo valve when I asked, saying it wouldn't make any change to the situation.

I'm not sure if I should go with what he is saying and replace the compressor, or try to replace the Duo Valve as shown in the scanner

Thanks for spending the time to read till here :smile, and I hope someone might have an idea to help me here

Plutoe

The compressor and the good ole duo valve are apart of two different systems: The compressor=AC; The duo valve=heating system. However if one of the duo valves is open that allows hot coolant to flow and disrupt the cooling.

One quick way to determine if the AC compressor is really compressing, is put a set of AC gauges on and look at the H and L pressure,is the high 15-17? If so you have a good compressor!

I trust diagnostics---I would change the duo valve and mechanic!!