My o7 tahoe will only blow hot air when set at 90 degrees. It will do this whether set on manual or automatic

SOURCE: 2001 tahoe front heater not working, rear heater blows warm air

Notorious for plugged heater cores. Also updated plastic restriction couplers mounted at heater core available from dealer. Try back flushing heater core. Run engine till its at operating temperature then carefully hold the inlet and outlet hose breifly with heater fan on high if hoses are nearly the same temp then flow is good , if not then core is plugged.

Jeffery Lewis

• 329 Answers
• Posted on Jun 03, 2009

SOURCE: 2004 Chevy Silverado AC is blowing warm air on passenger side.

You have dual zones that are controlled by temperature actuators the passenger side has lost its memory or has gone bad you can put it in self programming by disconnecting the battery for ten minutes then hook it back up start the truck turn the temperature control on but do not touch any other controls let it go thru the self programming for about 6 to 7 minutes then select your temperature you want if it still does not work properly you may have a bad actuator or a bad connection at the actuator

SOURCE: 2004 chevy tahoe, dual climate control, blowing different temps

Its more then likely the temp door broken or temp door motor broken/stuck. There is 2-3 of these motors under the dash on the side of the evap/heater core box. Some require extensive labor to replace, good luck

SOURCE: ford ka heater blows hot air all the time

Your problem is a faulty heater control valve. The design used on these vehicles allows for hot water to flow constantly and compete with the evaporator as there is no blender door. You have to replace the valve and possibly the control head. Meanwhile, you can bypass the valve to have cold air

SOURCE: ac blowing hot air

the blend door actuator located on the air box (right hand side under dash) is prob. inop. worst case senerio the blend door its self is broken. I have replaced the actuator more than anything.