buddy6210

I've check around the forum and haven't found anything that would help with the problem my car (2006 C230 Sport) is having. When I put my car's A/C in Auto, it will sometime work, but most of the time it either blows hot air or it will switch to full defroster. These changes can happen at start up or while I'm driving.

My mechanic pulled code "B15D0 COMPONENT M2/7 (RIGHT BLENDING AIR FLAP ACTUATOR) IS STIFF OR BLOCKED." I opened up the dash and the actuator seems to be operating properly.

Does anyone have any idea where I should start looking?

Moviela

Since it works sometimes we can assume that the compressor and Freon charge is OK. The intermittent nature points to poor connections or bad temperature sensors. You do need to find out why blending door is not reporting in properly. This could be the evaporator temperature sensor. If the system moves the door to reach a certain temperature in the cabin, but the reported temperature is not correct (usually reported as a super low temperature) the system will react by sending hot air to correct the incorrect super low temperature.

Glyn M Ruck

Have you disconnected the stepper motor & arm from the blending flap & ensured that the blending flap does not have tight hinges or is being restricted in some way? Stepper motor could also be faulty.

buddy6210

Thanks, I hadn't thought of checking the evaporator sensor but that would make sense. The blending door may have been an anomolly since it has not come back since being cleard. I took the dash apart and the actuator and arm are functioning, it's just that it changes to heat and blows out the defrost and floor vents whenever it wants.

buddy6210

Glyn M Ruck, thanks for your reply. I took the dash apart and checked the operation of the right blending door actuator and it appears to be operating properly. The motor engaes and moves the arm. The problem is that it randomly chages to max heat and directs all the air to the windshield and floor vents. Conversely, in the winter I've had it change from hot air to cold all of a sudden. The only way I can make sure to get either heat or a/c is to turn the temp knob to the extremes to place the system in manual mode.

buddy6210

Moviela, I changed the Evaporator Temp Sensor hoping that would fix the problem, but it didn't. I still get air out the floor vents blowing full blast when I put the unit in Auto. It can be either cold or hot air, likewise when I put it in manual and set the Temp Wheel anywhere in between Min and Max I get eihter hot or cold depending on what the car decides to blow. Any ideas where I should check now?

I did replace the control unit about a month ago.

Boom vang

I also have a problem with my AC over the weekend. it blows cold air on the passenger vents but the driver's side center vent blows warmish air. I figure that the compressor and refrigerant is fine as I can get ice cold air on the passenger side.

other than closing my vents and using the passenger side any suggestions of what is wrong, this is really bizzare.

in a previous posting people have mentioned the 'easter egg' of reseting or re-synching the HVAC unit but I can't find how it is done

it is 39*c in Toronto and I am dying and need a cool interior

For the US people that is 102f

samaritrey

You hold the right two bottom buttons until the lights flash back and forth. I think it is the recirculate and the defroster buttons (I am to lazy to look it up/ go to garage)
BTW my car had the same issue and it ended up being the stepper motor/linkage that controls the bleeding of the hot/cold air together to make the desired temp. I located the parts and they started working fine (after I had removed the entire dash looking to fix all the noises and could not find any issues) Haven't had the issue in two years or so now.
First step is to run the diag and see what happens if it runs forever then you need to locate the motor and linkage and see if it is just stuck or some other issue.