[tshown]

when I am driving the right side defrost vent is blowing cold. I would think it is heat flap servo, but where is it at. is this a common problem?

 

[volksfanatic]

It is possibly caused by a bad blend door motor.

 

[laxmid99]

when I am driving the right side defrost vent is blowing cold. I would think it is heat flap servo, but where is it at. is this a common problem?

Almost 5 years later and I am having the same/similar issue:

I am getting no heat out of the right side of my car. It is split right down the middle. My driver's (left side) vent and the driver's side of the center console's vent cluster will blow both cold and hot air when selected (to include the foot well and the windshield defroster). My passenger's (right side) vent and the passenger's side of the center console's vent cluster will only blow cold air, even when heat is selected (to include the foot well and the windshield defroster). This happens no matter what is selected i.e. re-circulation, A/C, defrost, bringing air from outside, etc.

The air is not being obstructed at all. With the fan on full, there is no difference in the amount of air coming out the driver, center or passenger vents at any location (when selected) i.e. foot well, chest, or defrost. This is solely a temperature issue that only affects the passenger side of the car.

Can you tell us all what you did to fix your defroster problem? Was it this "blend door motor"

 

[Ardi]

I probably won't see the OP reply, since I was looking for another problem for my CC. I read your problem and decided to register to give you an answer.. your problem has to do with the temperature sensor. Since is a Dual Climate Zone, there's a temperature sensor on the left and right side of the vent. That sensor comunicates with the ECU. Whenever the sensor goes bad, it sends wrong information (temperature readings) to ECU.
I.E., you have the heater blasting on both sides, right?
Now, the drivers side blows hot (80F), but the passengers side blows cold. Driver's side vent sensor reads 80F so there's no problem there.
Passenger's side however, when sensor goes bad, it reads somewhere around 160F. The ECU "sees" this, and its trying to "compensate" by turning the heat lower on the passenger side.

Long story short, remove the side cap/cover on passenger side, you'll see the sensor on the duct installed upwards. Remove it, replace it with one from junkyard or a new one. Your problem will be solved!

 

[laxmid99]

I probably won't see the OP reply, since I was looking for another problem for my CC. I read your problem and decided to register to give you an answer.. your problem has to do with the temperature sensor. Since is a Dual Climate Zone, there's a temperature sensor on the left and right side of the vent. That sensor comunicates with the ECU. Whenever the sensor goes bad, it sends wrong information (temperature readings) to ECU.
I.E., you have the heater blasting on both sides, right?
Now, the drivers side blows hot (80F), but the passengers side blows cold. Driver's side vent sensor reads 80F so there's no problem there.
Passenger's side however, when sensor goes bad, it reads somewhere around 160F. The ECU "sees" this, and its trying to "compensate" by turning the heat lower on the passenger side.

Long story short, remove the side cap/cover on passenger side, you'll see the sensor on the duct installed upwards. Remove it, replace it with one from junkyard or a new one. Your problem will be solved!

Thank you so much for the reply.

I was really hoping what you suggested was the problem back when I was troubleshooting. I found a you tube video that went over exactly what you wrote about with the sensors. They are a pain to get to. Unfortunately/Fortunately the sensors were all working. Next, I thought about blockage in the heater core, so I back flushed and I couldn’t believe the amount of debris that came out. I bought this car used, I live in a very warm climate, and I do not think people take care of their radiator systems like people from colder areas do... Things got better, but not 100%, not even 50%. I did the flush a few times more with no additional increase in heat to the passenger side vents. So I brought it into the shop (crossing my fingers it would be something easy and/or cheap that I overlooked).

My fears were 100% confirmed, the shop diagnosed it was the heater core. I knew this would be the most expensive repair, I was really holding onto hope that I mis-troubleshot a sensor or vent flaps needed to be rest... $250’ish for the part, another $600’ish for labor. Problem was solved, the car had heat on all vents... Atleast I thought the problem was solved. Roughly two weeks later I had condensation on the Front window and a puddle on my floorboard. The heater core had a pin hole defect from the factory. Everything was under warranty, even got a rental. It’s been a few months and hundreds of miles with no issues.

I got to see both of the bad heater cores. I took the first one home and cut it open. It was ten years old and I do not believe any amount of flushing would have fixed the amount of build up LOL. I couldn’t see the hole on the second, but when fluid was poured in, fluid would run out the vents. Somewhere in there was a break.