Front HVAC turning on and off when accelerating.

[lilsettals]

I have a 2004 Yukon with the dual zone automatic climate control. Last winter I went out to start my truck one morning after an overnight freeze and the front HVAC control module was on from the previous day I had drove my truck. All the buttons and lights worked on the control module but no air was blowing out of the vents. Then suddenly after driving it for a while the air randomly kicked on the settings I had it set to. I thought it was my blower motor resistor so I replaced it and it halfway fixed the problem. The control module would respond to the inputs but they were delayed and it still would turn on and off intermittently while accelerating. The only time it would stay on was when the fan speed was at its max level. So I changed the blower motor and still have the same problems. I changed the fuse for the blower motor and the front HVAC control module. What could the problem be. Should I replace the HVAC control module itself, it’s the only thing I have replaced. I also notice that some of the lights on the control module started to go out or go dim. What should I do?

 

[Doubeleive]

I have a 2004 Yukon with the dual zone automatic climate control. Last winter I went out to start my truck one morning after an overnight freeze and the front HVAC control module was on from the previous day I had drove my truck. All the buttons and lights worked on the control module but no air was blowing out of the vents. Then suddenly after driving it for a while the air randomly kicked on the settings I had it set to. I thought it was my blower motor resistor so I replaced it and it halfway fixed the problem. The control module would respond to the inputs but they were delayed and it still would turn on and off intermittently while accelerating. The only time it would stay on was when the fan speed was at its max level. So I changed the blower motor and still have the same problems. I changed the fuse for the blower motor and the front HVAC control module. What could the problem be. Should I replace the HVAC control module itself, it’s the only thing I have replaced. I also notice that some of the lights on the control module started to go out or go dim. What should I do?

The digital dual zone control unit's are known for doing this, may work at startup and then quit after a few minutes or will randomly work/not work
stupid things are not cheap though and then if that's not it then it's a real kick in the pants.
and it's really hard to troubleshoot