Heating Insufficient

Steps 1-5:

Steps 6-19:

Steps 20-27:

DIAGNOSTIC AIDS
The most likely causes of insufficient heating outside the heater system include the following:
^ A low coolant level
^ A faulty thermostat
^ A partially or fully clogged heater core or hose
^ An obstruction to the air circulation
^ An air leak past a faulty seal into the passenger compartment