'02 E320 Climate Control Problem

I've seen lots of messages from members who have had problems with not enough cold air from the A/C but I've got the opposite problem.

There is supposed to be two zone climate control in the car but it doesn't seem to work very well. With the driver's side set to 73 degrees F and the passenger's side set to 73 degrees, things start out ok. The climate control is set to automatic. After about 20 minutes, the passenger is getting cold and turns up the temperature - first to 75, then 77, 79, 82,83 - no effect. Still cold air is coming out of the vents on both the driver and passenger sides.

After about ten minutes more, I'm starting to get cold too and turn up the temperature. With both controls set to 83 degrees, cold air is still coming out of the vents. It is about 75 degrees outside and the sun is shining brightly on the dash.

If both sides are set to 84 (setting either side to 84 doesn't help), warm air now starts to come out of the vents.

The dealer has replaced the cabin control sensor but the problem still remains and they say they don't see a problem.

Any suggestions?

[mbdoc]

On the W210 chassis we have seen the receiver-drier cause this problem due to restriction!!