Defrost has two different temperatures at the same time (2008 Extended cab)

[Titan4]

I have a 2008 Extended Cab and every once in a while my defrost air will be a different temperature on the driver's side than it does on the passenger side. When it happens the driver's defrost air will be warm while the passenger defrost air will be cold. It results in the passenger side fogging over while the driver's side does not.

Mine does have the separate temperature controls for the passenger, BUT this feature is automatically disabled when defrost mode is selected - as it should be (since you would never want the defrost air temperature to be different on each side).

Anyone else ever experience this? I will take it to the dealer since it is under warranty.

[brcidd]

The dealer can monitor temp door positions- evidently the temp doors are not in synch when in defrost mode- may need tobe reprogrammed- or reset- but it will take a Tech II to read the codes set and reset the doors..

[Titan4]

I took it to the dealer and they were not able to find anything wrong. That is the nature of the beast I guess with intermittent problems. It will surely happen again, but I will need some luck for it to happen when I take it back to the dealer again.

[Titan4]

I decided to measure the defrost air temperature difference between the passenger side and driver's side. First I set the temperature to 71 degrees. Then using a digital thermometer I first measured the air temp out of the extreme right side of the passenger defrost vent register and then moved it to the extreme left side of the driver's defrost vent register. Here is what I saw:

Passenger side defrost air temp: 64 degrees
Driver's side defrost air temp: 84 degrees

Unbelievably a 20 degree difference! The difference appears to lessen as you set your temperature towards the extremes (full cold to full hot), but I have not systematically measured those settings yet.

I gave the dealer my data and they basically confirmed my readings, but in the end did not find anything wrong. They essentially said that must just be the way it is. They saw the same thing on another truck there too. A friend of mine has a 2008 Silverado and while he has not measured the difference he says he can feel the difference.

I would like to hear from some of you. Put your system in defrost mode (only defrost - NOT the defrost/feet combo) and set the temperature to 71 degrees. Then feel the difference between the driver's side and passenger side defrost vent registers.