Answered By: Andrew Tadman
Last Updated: Sep 14, 2015     Views: 1591

We can't specifically tell you what is wrong, but I checked our Auto Repair Reference Center database. You can access this from home with your library card. They have a troubleshooting section and this is what they have listed for that issue:

Heater blows cool air

  • Check the engine coolant level. If the coolant level is low, top off and bleed the air from the cooling system as necessary and check for coolant leaks.
  • Check engine coolant operating temperature. If coolant temperature is below specification, check for a damaged or stuck thermostat.
  • Check the heater control valve operation. Check the heater control valve cable or vacuum hose for proper installation. Move the heater temperature control from hot to cold several times and verify the operation of the heater control valve. With the engine at normal operating temperature and the heater temperature control in the full hot position, carefully feel the heater hose going into and exiting the control valve. If one heater hose is hot and the other is much cooler, replace the control valve.

We also have a mostly complete set of Haynes, Mitchell, and Chilton's car repair manuals.