HVAC problems with GMC Sierra
I have an SLE model GMC Sierra 2500. I do not have the automatic controlled cabin temperature. I do have the driver/passenger side split selector for the temperature.
Here are my symptoms:
1) Unusual "squeak" noise coming from the dash when the temperature selector(*) is(are) close to the coldest setting;
2) At random times (could hit a bump, or just smooth riding; effectively unpredictable) the driver side will start blowing hot air, while the passenger side maintains temperature at its setting.
Does anyone know what causes this? The most significant problem is the temperature jumping straight to hot. It can be immediately corrected by turning off the truck, and starting it up again, and it is usually fine for some indeterminate amount of time.
If there is an easy cause, is there an easy fix? A relay perhaps?
Any help would be much appreciated!