'99 E430--HVAC problem
 

A/C is set on automatic--driver's side vents blow warm air while passenger side vents blow cold air--set on 68 degrees. Any input as to the cause?

Normally that is caused by a low level of refrigerant. Have it checked with gauges to see what the pressures are and have it topped off if necessary.

Thank you Stan BUT, I would think that both sides would blow warm if refrigerant is low--only drivre's side blows warm--passenger side blows COLD.

I work on these cars for a living. Trust me. Check the AC charge.

Thank you Stan. Can you tell me if the ambient temp is 85 degrees, what should the low and high side preasures be on this car??

Thank you mucho!!

I have the same problem
 

I had to turn on the AC this weekend and driver side blows warm while passenger side blows cool not cold. I guess I need to check the charge.
Last year all was fine, does this mean I have a leak?

johneb48 - did you fix your problem and what were the pressure raedings ?

On the W210, the first sign of a declining charge of R134 is a temp difference from left to right. It's the way the evaporators are configured.

Don't just top-off the system. These are sealed systems and odds are you have a leak somewhere.

Also, don't rely on either high side or low side pressure readings. Low side are nearly constant thanks to the variable pressure nature of the system. High side pressure values can be all over the map depending on cooling requirments.

1 can fixed it
 

I took Stan Pittman advice and topped off the system with a can of refreigerant (13 oz) and all is well now. I know I must a slow leak somewhere but it probably will be too dificult to find out. It leaked over the winter. When it gets worse I will try to find out where it is leaking.

I did not check any pressures I only found the low pressure side or the gas side of the system and added the reregerant after bleeding the lines a bit to minimze air/moisture injection into the system.