Dual Zone Climate Control Problems

DaveEd · May 10, 2005

I recently purchased a 2003 Yukon SLT and am having problems with the electronic dual zone climate control. Unfortunately, it is now out of warranty with 62,000 miles. Regardless of what temperature I have it set, in the “Auto” mode the fan stays on the highest setting and only blows very cold air. Even on a long trip, the fan speed does not go down from the highest and occasionally the second highest speed setting and the air stays real cold. The only way to get heat is to set the temperature all the way up to 90 degrees and then some warm air comes out, but again the fan stays on high speed. The only way for me to moderate the temperature is to manually set the fan speed and turn the ac button on/off, or the whole unit on/off. Thankfully, I have heated seats for warmth!!! I have not checked if the rear seat climate control is working or not. I spent all my money on the truck, so would like to fix it myself, if possible. I am assuming that the problem is with the dash control unit or the actuator that controls the mixing doors or the temperature sensor(s). I would greatly appreciate any guidance on diagnosing and fixing this problem. Thanks in advance for the help!

Added: I am hoping that someone else out there has experienced something similar and can offer advice. I posted this same question to the GM Tech who recommended further diagnosing first. The local dealer wants $150 just to diagnose the problem. Help!

michaelrayce · May 10, 2005

I recently purchased a 2003 Yukon SLT and am having problems with the electronic dual zone climate control. Unfortunately, it is now out of warranty with 62,000 miles. Regardless of what temperature I have it set, in the “Auto” mode the fan stays on the highest setting and only blows very cold air. Even on a long trip, the fan speed does not go down from the highest and occasionally the second highest speed setting and the air stays real cold. The only way to get heat is to set the temperature all the way up to 90 degrees and then some warm air comes out, but again the fan stays on high speed. The only way for me to moderate the temperature is to manually set the fan speed and turn the ac button on/off, or the whole unit on/off. Thankfully, I have heated seats for warmth!!! I have not checked if the rear seat climate control is working or not. I spent all my money on the truck, so would like to fix it myself, if possible. I am assuming that the problem is with the dash control unit or the actuator that controls the mixing doors or the temperature sensor(s). I would greatly appreciate any guidance on diagnosing and fixing this problem. Thanks in advance for the help!

Added: I am hoping that someone else out there has experienced something similar and can offer advice. I posted this same question to the GM Tech who recommended further diagnosing first. The local dealer wants $150 just to diagnose the problem. Help!

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i think the easiest way would be to get a new controller from somewere , maybe ebay and swap them , then you would know if its the controller or something more .

71GMC_3/4T · May 10, 2005

I would take a look at the temperature sensor that's above and to the left of the driver's head, and the wiring for it. Sounds like it thinks it's really friken hot all the time and trying to cool it down, hence the full blast cold air.

Last winter, when I was still new to my truck, if the sun warmed up the interior it would crank the cooling on full bore, in the middle of winter! That's why I think you have a bad sensor up there.

Sorry, but I can't tell you how to check it to see if it's functioning properly. You might post on the GM Expert part of the forum to learn more about it.

D_Ying · May 10, 2005

My 01 Denali does the same thing if I have the back AC turned off. But after turning it on the front fan speed will slow down and it will maintain a comfortable setting.

DaveEd · May 17, 2005

I replaced the electronic climate control head unit, but it did not fix the problem. I removed the access cover to the mixing door actuator by the center hump and watched it as I turned the temperature all the way hot (the only way to get any warm air). The exposed metal piece only moved ¼ of a rotation at most. Is the actuator motor likely the problem? Are there any other items that I should check, such as the overhead temperature sensor and if so what should I look for? Any advice would be appreciated. Thanks!