Ford has issued TSB 98-6-3 that addresses this issue.
Affected models that we are aware of:
1997 Lincoln Town Car
1997 Mercury Grand Marquis
1997 Ford Crown Victoria
The first step is to verify the presence of codes 024 or 025.
- Stabilize the temperature of the vehicle.
- Press "OFF" and "Floor" at the same time.
- Let go, and immediately press the "AUTO" button.
- You should see segment check for 20 seconds.
- All segments will display simultaneously if no codes are found.
- Press "DEFROST" to exit self test.
If code 024 or 025 is accompanied with a clicking sound, replace the blend door actuator.
Ford states the noise is caused by a broken gear within the actuator. Ford has revised the design of the actuator so the gear is less likely to break.
Plan for 3 or more hours labor to replace this actuator.
Note: If complaint is no temperature control and you do not have a "clicking" sound, but have codes, see the service manual for pinpoint tests.
We have found that running self test may revive a stuck actuator in some cases.