Climate control and belt squeal

[andyems]

I actually have two questions about my 2007 GMT-900 Silverado. First, on two instances in the past month my maual climate control will not switch to heated air. I turn the dial all the way into the red, but it still blows cold air. Of coarse, the truck is warmed to normal temp and should be blowing warm. i turn the dial back and forth a few times and it starts blowing warm again. This has only happened twice in the past few weeks, other times it works fine. I just don't know if the temp control if vacuum or electronically controlled in this truck so I don't know how I need to go about diagnosing and fixing the problem.

Second, every time I start my truck cold, I hear the belt squeek or chirp for about the first 20-30 seconds then it goes away. I never hear it except when I start the truck and the engines cold/cool, such as sitting overnight, cooler outside temps, etc. It goes away after a few seconds and I never notice it when the motor is warmed and it has been driven in the past several hours.

Thanks for the help.

[schlegle1]

typical GM's the belts get moisture on them from sitting/the weather outside and tend to squeal until the truck is warmed up. They all do it, no big deal. If it continues to do it for longer periods check your belts for wear and check your pulleys.

[Morgan1986]

my belt makes noises for the first couple mins and then goes away . Never did that when it was new, my belt looks go tho