Temperature is controlled by electric-actuated blend-air door, located on evaporator case. The blend-air door can be closed or opened, allowing cooled or heated outside air to be discharged from outlets.
TEST E: INSUFFICIENT, ERRATIC OR NO HEAT
Check For Proper Engine Coolant Level
Check engine coolant level hot and cold. If coolant is at proper level, go to next step. If coolant level is incorrect, go to step 3) .
Check For Hot Coolant To Heater Core Inlet
Start and run engine to normal operating temperature. Set control to full heat. Feel heater core inlet hose. If heater inlet hose is hot, go to step 4) . If hose is not hot, check cooling system and hoses. Repair as needed. Retest system.
Check Coolant System For Leaks
Ensure cooling system is filled to specified level. Perform cooling system pressure check. If system holds pressure, go to next step. If system does not hold pressure, repair system as needed. Retest system.
Check Heater Core Outlet Hose For Hot Water
With engine at normal operating temperature, set control to full heat. Feel heater core outlet hose. If heater core outlet hose is cool, repair heater core for plugged condition. If outlet hose is hot, test electronic blend door actuator.
Dec 20, 2016 at 6:19 PM
