Operation CHARM: Car repair manuals for everyone.

Test H

PINPOINT TEST H: INSUFFICIENT, ERRATIC OR NO HEAT


Test H1-H4:






Test H4 Continued:






Normal Operation
Under normal operation, warm coolant flows from the engine through the heater core and back to the engine.

Possible Causes
- Plugged heater core.
- Coolant level.
- Temperature blend door.