115 is not a code in service manual. Here is the test procedure and loist of codes.
Section 12-03C: Air Conditioning System, Electronic Automatic Temperature Control 1996 Aerostar/Ranger/Explorer Workshop Manual
DIAGNOSIS AND TESTING Procedure revision date: 05/18/2000
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Self Test
Perform EATC on-board diagnostic test. Record all diagnostic trouble codes (DTCs) displayed during test.
The control assembly will detect electrical malfunctions occurring during the on-board diagnostic.
Ensure that the engine is warm (at least 49°C [ 120°F]) coolant temperature). To display the DTCs for the malfunction detected, initiate the on-board diagnostic by pushing OFF and FLOOR simultaneously and then AUTOMATIC within two seconds. The test may run as long as 20 seconds, during which time the display will be blank. If the display is blank for more 20 seconds, go to Symptom Charts when On-Board Diagnostic Test and Functional Test Indicate NO ERROR.
The on-board diagnostic test can be initiated at any time, with the resulting DTCs being displayed. Normal operation of the system stops when on-board diagnostic is activated. To exit the on-board diagnostic and restart the system, push the blue button. Pushing the DEF button instead of the blue button will clear all DTCs. The on-board diagnostic should be deactivated before turning the EATC system OFF. Refer to the following chart for an explanation of DTCs.
If a malfunction exists but no DTC appears during the test in Step 1, refer to the appropriate pinpoint test(s) contained in this section.
INSPECTION AND VERIFICATION FOR DIAGNOSTIC TROUBLE CODES Condition Possible Source Action
DTC 024
Blend door calibration during self-test.
REFER to Pinpoint Test A.
DTC 030
Self-test indicates automatic temperature control sensor shorted.
REFER to Pinpoint Test K.
DTC 031
Self-test indicates automatic temperature control sensor open.
REFER to Pinpoint Test K.
DTC 040
Self-test indicates A/C ambient air temperature sensor short.
REFER to Pinpoint Test G.
DTC 041
Self-test indicates A/C ambient air temperature sensor open.
REFER to Pinpoint Test G.
DTC 050
Self-test indicates A/C sunload sensor short.
REFER to Pinpoint Test H.
DTC 025
Intermittent fault in blend door calibration.
REFER to Pinpoint Test A.
DTC 042
A/C ambient air temperature sensor intermittent short.
REFER to Pinpoint Test G.
DTC 043
A/C ambient air temperature sensor intermittent open.
REFER to Pinpoint Test G.
DTC 052
A/C sunload sensor intermittent short.
REFER to Pinpoint Test H.
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