- Perform the defrost mode function test to ensure proper system
operation. Refer to Function Test (Pontiac)
or Function Test (Oldsmobile)
.
| • | The A/C compressor clutch is engaging. |
| • | The air flow from the proper outlets. |
- Inspect for an obstruction in both of the defroster nozzles.
Perform the following steps, as necessary:
| • | Remove any foreign objects. |
| • | Repair any loose instrument panel pad that blocks an outlet. |
- Inspect for the proper operation of the defroster air valve.
- Inspect for one of the following conditions.
Replace the defroster vacuum actuator or hose if one of the following
conditions exist:
| • | A faulty defroster air valve vacuum actuator |
| • | A faulty defroster air valve vacuum hose |
- Inspect for insufficient heating. Refer to
Heating Performance Diagnostic
.
