Here's what I experience:

1. AC works fine.

2. Heat works fine.

3. With moderate outside temperature (say, above 40F), everything seems to work fine: I can set a temperature, set everything to auto, and I will get variation in fan speed, variation in air temp from vents...things seems to settle at the temp I want...although I have noticed I have to set things pretty close to a fully cold position.

4. HOWEVER, when it's cold outside (this morning 25F), when the system is on it will always blow hot even after it warms up in the cabin. The only way to get cooler air is to click the wheel to the AC position.

What would/might account for this? Ordinarily with a problem like this I would think it's that temp sensor that goes to the CCU. But, as I say, everything seems to work fine above a certain ambient temp.

Thanks.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 160k miles
06 E320 CDI "Rutherford", Black on Tan, 180k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 79k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife