Help: Hvac issue

[Mike_S]

'04 GMC crew with the manual dual zone controler. Issue im having is at random times the driver side goes to full hot, and no amount of changing the temperature slider or turning the unit off and on will change it. Pass side has not done this that im aware of, and the only way i have found to get it to operate correctly is to shut the ignition off for a few seconds and restart. Then it opperates normally. Sometimes it works fine, some days it will do it 4 or 5 times. Any input?

 

[chevyburnout1]

Sounds like the temp actuator itself is failing for the driver's side. The position sensor internal to the actuator is probably seeing an intermittent or over-travel condition. Once it see's that it defaults to one max direction then stops operating until power is cycled from it.

 

[derekdmax]

My 06 does the same thing stealership told me it was the actuator motor going bad. When it does act up it goes to its default position and that happens to be full hot. They told me it was a 300 for the part