W211 Aircon/Duovalve Problem?

[E55BOF]

The car is an '03 S211 on 126K miles. The climate control blows cold - refrigerated cold, not ambient air temperature (22.5 deg. today) - all the time, even with the control temperature set to High or with demist selected. I presume the duovalve has seized, but is there a problem with the aircon control system as well (probably... - we need an Eeyore emoji...)?

 

[mersum1es]

Usually watervalve malfunction means hot... soounds like wrong temp sensor reading or stuck inner flap... by SDS you can see all sensor data and control flaps individually

 

[E55BOF]

Just read the codes with the iCarsoft - DTC B10/4 - In Car Temperature Sensor - current and stored. I hadn't thought of that, but Bingo! (I hope...).

 

[E55BOF]

Ordered a new cabin temperature sensor yesterday; it will arrive on Tuesday. The system is working normally today...

I put it out of and back into 'auto' a couple of times, adjusting the fan speed manually in between, and that seems to have cured it, for now at least. I'm wondering if there might be an intermittent fault/poor connection
in the control unit or wiring, though no fault code other than the sensor showed up. I hate intermittent electrical faults...