Need help

[Kenny Miller]

My 2015 Colorado cooling and heating is not working right. If I turn it up to hi I get hot air but just 1 deg down to 89 it starts blowing cold. I've tried it on auto and manual with no luck. I've tried all the diff buttons to change where the air comes from with no luck. Please help.

[BringTheRain403]

Sounds like a solenoid

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[CamGTP]

With all the electronics in the HVAC system I would have this on the scan tool to and diag the problem.

 

I don't know about these trucks but I remember working on a Volkswagon EOS (little compact car) and it had mini temp sensors in the hvac system. Well one went bad on the drivers side and it the temp was dropped off of the high settings it blew cold out the vents. I needed a scan tool to watch all the HVAC parameters and I found that problem.

[Kenny Miller]

Thanks for the input!!!