Climate Control 2000 E320

[jlbarnes]

Blows cold (refrigerated ) air when set for 80 degrees and outside temp is below 70 degrees. When set for "HI" temp, the heat does come on. Is the climate control thermostat unit failing or is there something else I can check? Also, does the unit detect daylight versus night? Sometimes it works ok when starting from inside garage then next time started after setting outside in sunlight, I get the previous problem of cold air.

[Matt L]

Check the temperature sensor aspirator fan. The vacuum should hold a 1cm by 1cm piece of paper to the vent (near the mirror), if it is working.

[ohlord]

the onboard diagnostics.
How to Diagnose Air Conditioning Malfunctions | EclassBenz.com
post the values and the errors.
take it from there
ohlord

[jlbarnes]

The temperature sensor aspirator fan is working as a 1cm x 1cm paper is attracted to it. Thank you for that tip but the problem still exists.

[ohlord]

the tests and post the values and errors.
ohlord

[Musikmann]

Originally Posted by jlbarnes

...does the unit detect daylight versus night?...

Yes. In the middle of your dashboard you can see a little hump. That contains a sunlight sensor which if working properly will raise the fan speed a notch or two (at least when you are in A/C mode). I don't think it plays any role if you are trying to heat the interior.