Poor Heater Performance

Some 2015-2016 Colorado and Canyon models may have poor heater performance with the HVAC system only blowing cold air. Relearning the HVAC doors may temporarily eliminate this condition.


Remove the temperature actuator and inspect for a cracked or broken shaft on the temperature valve. (Fig. 13) If the shaft is cracked in only one place, install a #4 hose clamp over the temperature valve shaft. (Fig. 14) It is not necessary to remove the door to add the clamp.


F13 shaft 1

Fig. 13


F14 shaft clamp

Fig. 14


If the shaft is cracked in more than one place or it is broken and has more than one piece missing, the temperature valve must be replaced.


– Thanks to Ken Cole

Transmission Adaptive Functions
Battery Discharged Overnight

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