climate control help
 

I have a 1993 300ce sportline that just started having problems with the climate control. The center vents only work when temp is max cold or hot, and the other day only hot air came out of side, top, and bottom vents no matter what the temp setting. It was @ 40 degrees (cold for California) and I could not regulate the temp. Any assistance would be appreciated.

The first thing to check are all the vacuum lines and then the vacuum motors, or pods.

Aspritation of the in-car temp sensor is critical for heat.

ALSO a hydro-locked heater valve will cause problems.

I have a very similar sounding problem on my 90 300TE. The temperature and fan work fine for a while, but the side vents will go to full heat without any action on the controls. Fortunately the fan does not kick into high speed. Only means we have seen to correct it is to shut the climate control off for a bit.

It seems to be worse if the selected temperature inside is close to the outdoor temperature. Then again it happened several times last weekend when the spread was 30-40 degrees (inside 65-70, outside 30ish).

When it is hot here in TX, the AC works as expected.

Any additional ideas beyond vacum system etc. already offered?

Thanks - MRK