Fault Code 15

Fig. 12 ATC wiring harness and lead connectors:

1. Remove ambient temperature sensor, then unplug from receptacle.
2. Using a suitable ohmmeter, check resistance between the two sensor terminals.
3. Resistance should be 3,000 to 40,000 ohms with ambient temperature between 30 and 120 degrees F.
4. If resistance is not as specified, replace sensor. If resistance is satisfactory, proceed to step 5.
5. Reinstall ambient temperature sensor, then remove computer control and disconnect electrical connectors.
6. Check resistance between terminal pins 9 and 18 of connector 7. If resistance is satisfactory, locate and disconnect wire connectors 2 and 3, then, using a suitable ohmmeter, check for continuity between pins of terminals shown, as follows:
a. Pin 7 of 3 to pin 9 of 7.
b. Pin 6 of 3 to pin 18 of 7.
7. If continuity test is satisfactory, repair harness lead between connectors 2 and 4.