For 1990-2009 cars

1. Inspect for the incorrect operation of the controls.

Advise the driver of the proper operation of the controls.

2. Inspect the engine for low engine coolant level.

Perform the following steps, as necessary:

• | Add coolant.

• | Inspect the engine for coolant leaks.

• | Run the engine in order to clear any air locks.

3. Inspect for a faulty engine thermostat.

Replace the thermostat, if necessary.

4. Inspect for a kinked heater hose.

Perform the following steps, as necessary:

• | Straighten the heater hose.

• | Replace the heater hose.

5. Inspect for obstructed heater core tubes.

An obstruction usually causes a squishing noise in the heater core.

Perform the following steps, as necessary:

• | Remove any foreign material from the heater core.

• | Replace the heater core.

6. Inspect for one of the following conditions:

• | A faulty blower motor

• | Replace a faulty blower motor.

• | A faulty blower circuit

• | Repair or replace faulty wires or connections.

7. Inspect the duct work for the following conditions:

• | The proper installation

• | Obstructions

8. Inspect the following components for the proper installation and the proper operation:

• | The temperature lever

• | The temperature motor