Aircondition problem

[Norse]

Hi.
I have the 4 zone digital climate control in my car. The problem is that the temp. on the air in the rear nozzles suddenly goes from the preset cool to really warm. Anyone know if there is a sensor somewhere which can be faulty??

 

[Diesel Benz]

Hi.
I have the 4 zone digital climate control in my car. The problem is that the temp. on the air in the rear nozzles suddenly goes from the preset cool to really warm. Anyone know if there is a sensor somewhere which can be faulty??

I believe this too is from the heat exchanger shut-off motor, the valve at the front of the fire wall. At some point when the AC wants more cooling power, flaps are opened differently, the heater core is supposed to be cool at this point but because of the shut-off motor failing, hot water is still entering the core.

 

[Norse]

Ok, I see what you mean. But I am thinking that the motor is working partially. It is working ok for 5-10 minutes, and then suddenly it gets warmer in the back. Must be that the motor is opening the valves to a wrong position.

It might not be the biggest problem since I live in the northern parts of Norway, and we rarely gets temperatures over 20c Most of the time I need to use the heater......

 

[Diesel Benz]

Ok, I see what you mean. But I am thinking that the motor is working partially. It is working ok for 5-10 minutes, and then suddenly it gets warmer in the back. Must be that the motor is opening the valves to a wrong position.

It might not be the biggest problem since I live in the northern parts of Norway, and we rarely gets temperatures over 20c Most of the time I need to use the heater......

If it is the shut-off valve, you might loose heat at some point if the valve stops operating at a closed position.

I'm not sure at all but I'm assuming the AC system is actually opening and closing air flow control flaps properly and you get cold air at the rear if only partial AC power is needed but hot air gets blown when the AC tries to increase cooling power (sounds odd but it would work if the valve was working fine).

The valve probably works intermittently but eventually stops and then you may have problems at winter.

DIY: Installing a new Changeover/Heater Control Valve - MBWorld.org Forums

 

[Norse]

Oh MAN.. Thank you SO much for the Great link and the reply.. Now I am confident I can just change the valve myself.