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DTC B1C84-14: Rear Window Defogger Relay Circuit Malfunction: Notes

WARNING: This page is about a different car, the 2018 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
DTC B1C84:14 (FRONT BODY CONTROL MODULE (FBCM)) DETECTION CONDITION AND POSSIBLE CAUSE

Description Rear Window Defogger Relay Circuit Malfunction
Detection condition
  • Front body control module (FBCM) detects an open circuit or short to ground in the rear window defogger relay circuit with the ignition switched ON (engine off or on).
Fail-safe Not applicable
Possible cause
  • Rear window defogger relay malfunction
  • Front body control module (FBCM) connector or terminal malfunction
  • Short to ground in wiring harness between rear window defogger relay terminal E and front body control module (FBCM) terminal 1P
  • Open circuit in wiring harness between rear window defogger relay terminal E and front body control module (FBCM) terminal 1P
  • Front body control module (FBCM) malfunction
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