When it is cold, and I use heater. I set the temperature, say 76.
The heater runs/works but then in about 1-2 minutes about 80% of time the temperature gauge (digital) starts going down to 60 and heater/vent starts blowing cold.
I reset the temperature to 76, but then again after 1-2 minutes, the temperature gauge starts going down and cold air starts.

This repeats about 8-10 times, and then all works after about 30-45 minutes.

What could be wrong?

Thanks for aall your help.

 

to avoid 20 questions, it helps to identify what your are talking/asking about.

 

Right off the bat, sounds like a bad or improperly programmed CCM. If it weren't an electrical issue, you'd experience the cold air without the climate control thermostat going down; then you'd be looking at maybe a heater core issue.
But I'd start with the CCM, if we're trying to diagnose it ourselves here.

 

Welcome.
Putting some basic truck info in a sig, helps members help you..
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