Have a 150 but help is needed on 2005 350. The center **** on the heater does nothing turning blue to red and back. No matter where I set the **** on the passenger side it blows hot air even when air conditioning is on. Only stops in off position. Any suggestions would be appreciated. Thanks Fred

 

Your blend door actuator isn't working. Probably needs a new motor. Old trucks ran off a vacuum, new models use a motor to move the blend door.

 

Thanks will check it out Fred