DTC Troubleshooting: B1241 (N and A/C ON)
  1. Check for continuity between the following terminals of heater control unit connector B (12P) and the power transistor 4P connector.
    12P:
    4P:
    No. 5
    No. 1
    No. 6
    No. 3

Is there continuity?
YES -
Go to Step 20 .
NO -
Repair open in the wire(s) between the heater control unit and the power transistor.■
  1. Turn the ignition switch to ON (II).