DTC Troubleshooting: B1240 (J and A/C ON)
Check for continuity between body ground and heater control unit connector A (28P) No. 7 and No. 8 terminals individually.
Is there continuity?
YES
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Repair short to body ground in the wire(s) between the heater control unit and the mode control motor.■
NO
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Substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit .■