A/c-Heater System - Automatic: Diagnosis Lincoln Mark I

ATC PRELIMINARY INFORMATION & TEST SEQUENCE

The ATC control panel can use self-diagnostics to locate system faults. If actuator fault is detected during normal operation, the VFD or function LED will blink.

Perform ATC SYSTEM FUNCTIONAL TEST. Record all error codes displayed during self-test. If error codes appear, follow diagnostic procedures outlined for each error code recorded.

In-vehicle temperature should be greater than 50°F (10°C) for proper system evaluation. If a malfunction exists and no error code appears during self-test, go to SELF-TEST INDICATES NO ERRORS FOUND in this article.

ATC SYSTEM FUNCTIONAL TEST

1. Turn ignition off, then on, to reset system. Ensure coolant temperature is at least 120°F (49°C). With system in automatic mode, set temperature on ATC control panel to 90°F setting. Wait at least 40 seconds.
2. Ensure system operates on high blower speed and warm air discharges from floor ducts. Ensure fresh/recirculated air door is in fresh air position. Ensure warm air bleeds from defroster nozzle.
3. Enter self-test and record error codes displayed. Exit self-test mode. Diagnose system according to error code (if displayed).
4. With system in automatic mode, set temperature on ATC control panel to 60°F setting. Ensure system operates on low blower speed and then on high blower speed as temperature setting changes.
5. Wait 40 seconds. Ensure cool air is discharged from panel ducts. Ensure fresh/recirculated air door is in recirculated air position.
6. Enter self-test, record error codes displayed and exit self-test. Follow diagnostic procedures outlined below for each error code recorded. After service or repairs, repeat system functional test. If a malfunction still exists, go to SELF-TEST INDICATES NO ERRORS FOUND test.

Note. It is normal for A/C system to discharge cool air from panel ducts with temperature set at 85°F and engine idling. Drive vehicle for final check.

ATC SELF-TEST ENTERING SELF-TEST FEATURE

Note. ATC system has a self-diagnostic system to display error codes on ATC control panel. Before entering self-diagnostics, ensure coolant temperature is at least 120°F (49°C).

1. To activate self-test, depress OFF/AUTO and defrost buttons simultaneously and then A/C button within 2 seconds. see scheme 2 Self-test can be initiated at any time with the resulting error codes being displayed.
2. Normal operation is stopped when system is in self-test mode. To exit self-test, depress COOL button. The self-test should be deactivated before powering system down.

BLEND DOOR ACTUATOR TEST

BLEND DOOR ACTUATOR TEST (1)

Scheme 2

FLOOR/PANEL DOOR ACTUATOR TEST

FLOOR/PANEL DOOR ACTUATOR TEST (1)

FRESH/RECIRCULATED AIR DOOR ACTUATOR TEST

FRESH/RECIRCULATED AIR DOOR ACTUATOR TEST (1)

Scheme 3

SELF-TEST INDICATES NO ERRORS FOUND

Note. If self-test does not locate problem, refer to symptoms listed below. Perform test procedures and service as required.