2006 impala heater motor blows like normal but some mornings it blows cold if we shut it off and turn it on a couple of times it will blow hot and work fine. the heat gauge is at half way when the engine is warm and does not fluctuate it stays at half and always has since new. the ac is off

This problem is caused by a sticking air temperature control blend door actuator or blend door, this door moves back and forth to get the desired temp, the actuator is electronic and prone to this type of problem, suggest u replace it.

My car was doing the same thing and it turned out to be the electronic motor that was bad as the blend door was able to be moved manually. My brother in law was able to fix it underneith the steering wheel area once he verified the passenger side was working ok. The electronic motor or DORMAN 604-108 A/C Heater Blend Door Leverworks works for both sides of the car for dual climate control and the part number is 15844096 and is around $35. Once he replaced I was able to have hot and cold again!! I have a 2006 Chevy Impala LTZ....