Have a 99-E430. The other day when the AC was turned on it only blew cold air out of the right vents (including the right half of the center vent). It was very cold. But the driver side vents blew warm air. Now, a week later it doesn't blow cold air at all....only warm air from all the vents. The blower works normal. The refrigerant level is full and the compressor is engaging. What do you suspect could be the culprit? What things should I check to confirm? Thanks.

Typical would be low charge. The cold on the right warm on left is a distinct pattern with that car.

If it truely is full then the other part of the pattern is that any reduction in refrigeration capacity shows in that same way. Possible causes of such would be a restricted expansion valve or a variable displacement compressor that is being controlled to not pump. System pressures tell the story.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Also could be the DuoValve. Pinch off the hose feeding it and see what happens. It could be stuck in open position.

How did you determine that the refrigerant level is full? The ONLY way to know for sure is to evacuate and recharge by weight. If there is a restriction in the system, the pressures may look right but you will not have enough flow. Thus you cannot go by pressures alone to determine refrigerant fill. If you happened to just check the low-side port (running or not), this tells you absolutely nothing.

If the low-side and high-side pressures are within specifications and the system is performing as designed, you probably have the system full (or nearly so). If the pressures are within specifications but you do not have good performance, there is a problem other than refrigerant level.