Are the heater hoses warm soon after you start the truck? and does the heater put out warm air then?
Your blend door actuator could be bad, if the hoses are hot but not warm air in the heater
if the hoses are still not warm after several minutes after start, then you may have a different problem
Your blend door actuator could be bad, if the hoses are hot but not warm air in the heater
if the hoses are still not warm after several minutes after start, then you may have a different problem