EATC - Diagnostic Service Information

Article No. HEATER/AIR CONDITIONING - ELECTRONIC
87-10-10 AUTOMATIC TEMPERATURE CONTROL (EATC) -
SERVICE INFORMATION TIPS

MERKUR: 1988 SCORPIO


ISSUE: The Electronic Automatic Temperature Control (EATC) diagnostics are not published in the 1988 Scorpio Shop Manual. Complete diagnostics are being developed and will be part of the 1988 Scorpio Shop Manual supplement.

ACTION: If a service code is displayed on the LCD temperature display, use the following service information.

When the vehicle is started, the control module goes through a self-test routine. This checks the sensors, actuators, and affected circuitry. If a fault is present, a service code will be displayed on the EATC temperature display.

NOTE: If there are multiple failures, the sum (total) of all the service codes will be displayed.

Figure 10 - Article 87-10-10:

Figure 11 - Article 87-10-10:

Figure 12 - Article 87-10-10:

Figure 13 - Article 87-10-10:

The following service codes could be displayed if a fault is present with the components listed.

Service Code Components To Check

01 ........... Ambient air temperature sensor
02 ........... Interior air temperature sensor
04 ........... Discharge air temperature sensor
08 ........... Temperature blend door motor
16 ........... Air distribution door motor

Refer to Figures 10 through 13.

Example:

If a discharge air temperature sensor is disconnected (code 04) and the ambient air temperature sensor is disconnected (code 01), a code "05" will be displayed on the LCD temperature display.
If a service code is displayed, check for loose connections or broken wires. Refer to the 1988 Scorpio Electrical and Vacuum Troubleshooting Manual (EVTM) when checking circuit continuity between the EATC module and affected sensor. If

the service code is still present and the wiring is okay, replace the sensor.

OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY"