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Home >> Mazda >> 2016 >> 6 Touring, Standard Trans >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Seats >> Rear Seat Warmer Control Unit Inspection >> Inspection Procedure (No. 1 Rear Seat Warmer Function Is Inoperative) >> Diagnostic procedure

Diagnostic procedure

STEP INSPECTION ACTION
1 PERFORM DTC INSPECTION 
  • Perform instrument cluster DTC inspection.
  • Are DTCs and error codes output?
Yes Perform the diagnosis according to the inspection procedure for each code.
(See DTC TABLE [INSTRUMENT CLUSTER] .)
No Go to the next step.
2 DETERMINE IF THE MALFUNCTION CAUSE IS THE REAR SEAT WARMER SWITCH 
  • Select either Low, Mid, or High on the rear seat warmer switch.
  • Does the rear seat warmer switch LED illuminate?
Yes Go to the next step.
No Inspect rear seat warmer switch.
(See REAR SEAT WARMER SWITCH INSPECTION .)
3 DETERMINE MALFUNCTIONING SYSTEM 
  • Are the rear seat warmers on both sides not operating?
Yes Go to step 9.
No Go to the next step.
4 INSPECT THE REAR SEAT WARMER CONTROL UNIT POWER SUPPLY FUSE 
  • Inspect the R.SEAT W 20 A  fuse.
  • Is the fuse normal?
Yes Go to the next step.
No
  • If the fuse is deterioration:
    • Replace the malfunctioning fuse.
  • If the fuse is blown

    Repair the short to ground in wiring harness between the following terminals:

    • R.SEAT W 20 fuse and rear seat warmer control unit terminal O
    • R.SEAT W 20 A  fuse and rear seat warmer control unit terminal M
5* DETERMINE IF CAUSE OF MALFUNCTION IS CONTROLLER POWER SUPPLY WIRING HARNESS FOR REAR SEAT WARMER OR OTHER CAUSE 
  • Switch the ignition off (LOCK).
  • Disconnect the rear seat warmer control unit connector.
  • Measure the voltage at the following terminal (wiring harness-side):
    • Rear seat warmer control unit terminal O
    • Rear seat warmer control unit terminal M
  • Is the voltage B+  ?
Yes Go to the next step.
No
  • Repair or replace the open circuit at the following wiring harness.
    • R.SEAT W 20 A  fuse and rear seat warmer control unit terminal O
    • R.SEAT W 20 A  fuse and rear seat warmer control unit terminal M
6 VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN FRONT SEAT WARMER CONTROL UNIT POWER SUPPLY WIRING HARNESS 
  • Front seat warmer control unit connector are disconnected.
  • Switch the ignition off (LOCK).
  • Measure the voltage at the following terminal (wiring harness-side):
    • Front seat warmer control unit terminal K
  • Is the voltage B+?
Yes Go to the next step.
No
7* VERIFY IF MALFUNCTION CAUSE IS SHORT TO GROUND IN REAR SEAT WARMER CONTROL UNIT 
  • Rear seat warmer control unit connector on the side that is not operating is disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Rear seat warmer control unit terminal on the side that is not operating H and body ground
    • Rear seat warmer control unit terminal on the side that is not operating G and body ground
  • Is there continuity?
Yes Go to the next step.
No
  • Inspect the open circuit following.
    • Rear seat warmer unit terminal H and body ground
    • Rear seat warmer unit terminal G and body ground
  • Inspect the body ground connector terminals for poor connection.
  • Repair or replace the malfunction.
8* VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF REAR SEAT WARMER SWITCH SIGNAL 
  • Rear seat warmer control unit connector is disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Rear seat warmer control unit terminal I and rear seat warmer switch terminal C
  • Is there continuity?
Yes Go to the next step.
No
  • Inspect the open circuit following.
    • Rear seat warmer control unit terminal I and rear seat warmer switch terminal C
9* INSPECT REAR SEAT WARMER CONTROL UNIT AND REAR SEAT WARMER UNIT CONNECTOR 
  • Disconnect the rear seat warmer control unit and rear seat warmer unit connector on the side not operating.
  • Inspect the rear seat warmer control unit and seat warmer unit connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion).
  • Is there any malfunction?
Yes Repair or replace the malfunctions.
No Go to the next step.
10* VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF REAR SEAT WARMER UNIT CIRCUIT 
  • Switch the ignition off (LOCK).
  • Disconnect the rear seat warmer control unit connector.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Left-side rear seat warmer unit terminal P and A
    • Right-side rear seat warmer unit terminal N and B
  • Is there continuity?
Yes Go to the next step.
No Replace the rear seat back pad or rear seat cushion pad.
(See REAR SEAT BACK TRIM REMOVAL/INSTALLATION .)
(See REAR SEAT CUSHION TRIM REMOVAL/INSTALLATION .)
11 DETERMINE IF THE MALFUNCTION CAUSE IS REAR SEAT WARMER SWITCH 
Yes Troubleshooting completed.
No Replace the rear seat back pad or rear seat cushion pad.
(See REAR SEAT BACK TRIM REMOVAL/INSTALLATION .)
(See REAR SEAT CUSHION TRIM REMOVAL/INSTALLATION .)