hameline

A recently acquired 2006 CLK 350 has an aberrant climate control system. With the temp dialed down to 65 on both sides, set to auto, it cools very well. Move the temp settings to anything else in the auto mode and it blows hot air through the dash vents, defrost vents and sometimes towards the floor. There is a slight detent in the switch at 65 and moving it away from the full cold setting triggers the sauna.

If you shut off auto and use the fan speed switch while at 65, all is well. Raising the temp in this mode produces the same sauna like effect as if in auto.

If you've had a similar experience, what (if any) has been the correction?

Many thanks

JSH

2008 C300 4MATIC Luxury
2006 CLK 350

Rudeney

This is usually due to a faulty humidity sensor (thermistor) in the overhead console. The official repair is to replace the entire OHC ($$!) But if you are so inclined, there is a very inexpensive DIY:

http://www.benzworld.org/forums/c209...re-sensor.html

JimVonBaden

Is this sometimes intermittent?

Rudeney

Yeah, I think it can be. Try pulling fuse #9 (rear SAM, in the trunk) and see if this changes things. This will cut power to the OCP. I think without a signal from the thermistor, it will ignore it, but a bad thermistor will register wrong readings and cause heat. Oh, and antoher thing to try - lower the windows and see if it changes. My understanding is that the humidity sensor is not used with the windows open.