Diagnostic Procedure

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.

STEP	INSPECTION	ACTION
1	DETERMINE MALFUNCTIONING SYSTEM Are the seat warmers on both sides not operating?	Yes	Replace the seat warmer control unit. (See SEAT WARMER CONTROL UNIT REMOVAL/INSTALLATION .)
1		No	Go to the next step.
2*	VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF SEAT WARMER UNIT CIRCUIT Switch the ignition off (LOCK). Disconnect the seat warmer control unit connector. Inspect for continuity between the following terminals (wiring harness-side): Driver-side seat warmer unit terminal C-E Passenger-side seat warmer unit terminal D-F Is there continuity?	Yes	Go to the next step.
2*		No	Replace the seat warmer unit.
3*	VERIFY IF MALFUNCTION CAUSE IS SHORT CIRCUIT IN WIRING HARNESS OF SEAT WARMER UNIT CIRCUIT Inspect for continuity between the following terminals (wiring harness-side): Driver-side seat warmer unit terminal C-Body ground Passenger-side seat warmer unit terminal D-Body ground Is there continuity?	Yes	Repair or replace for a short to ground in the wiring harness.
3*		No	Replace the seat warmer control unit.