Insufficient Heating or Defrosting

Insufficient Heating Or Defrosting (1 of 2):

Insufficient Heating Or Defrosting (2 of 2):

TEST DESCRIPTION
The most likely causes of insufficient heating outside the heater system include a low coolant level, a faulty thermostat, a partially or fully clogged heater core or hose, an obstruction to air circulation or an air leak past a faulty seal into the passenger compartment. For an organized diagnosis procedure, refer to Charts (part 1 and 2).