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Home >> Mazda >> 2013 >> CX-5 Touring, AWD >> Repair and Diagnosis >> Body & Frame >> Seats >> Seat System >> Seat Warmer Control Unit Inspection >> Diagnostic Procedure

Diagnostic Procedure

DIAGNOSTIC PROCEDURE DESCRIPTION

STEP INSPECTION ACTION
1 PERFORM DTC INSPECTION 
  • Perform meter and climate control unit DTC inspection.
  • Verify the meter DTC inspection and clock output check mode.
  • Are DTCs and error codes output?
Yes Perform the diagnosis according to the inspection procedure for each code.
No Go to the next step.
2 DETERMINE IF THE MALFUNCTION CAUSE IS THE SEAT WARMER SWITCH 
  • Select either Low, Mid, or High on the seat warmer switch.
  • Does the seat warmer switch LED illuminate?
Yes Go to the next step.
No Inspect the climate control unit or clock.
(See CLIMATE CONTROL UNIT INSPECTION [FULL-AUTO AIR CONDITIONER] ).
(See CLOCK INSPECTION ).
3 DETERMINE MALFUNCTIONING SYSTEM 
  • Are the seat warmers on both sides not operating?
Yes Go to step 9.
No Go to the next step.
4 INSPECT THE SEAT WARMER CONTROL UNIT POWER SUPPLY FUSE 
  • Inspect the SEAT WARM 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 melt

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

    • SEAT WARM 20 A  fuse-Seat warmer control unit O
    • SEAT WARM 20 A  fuse-Seat warmer control unit M
5* DETERMINE IF CAUSE OF MALFUNCTION IS CONTROLLER POWER SUPPLY WIRING HARNESS FOR SEAT WARMER OR OTHER CAUSE 
  • Switch the ignition off (LOCK).
  • Disconnect the seat warmer control unit connector.
  • Measure the voltage at the following terminal (wiring harness-side):
    • Seat warmer control unit terminal M
    • Seat warmer control unit terminal O
  • Is the voltage B+  ?
Yes Go to the next step.
No
  • Repair or replace the open circuit at the following wiring harness.
    • SEAT WARMER 20 A fuse-Seat warmer control unit
6* VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN SEAT WARMER CONTROL UNIT POWER SUPPLY WIRING HARNESS 
  • Seat warmer control unit connector are disconnected.
  • Switch the ignition off (LOCK).
  • Measure the voltage at the following terminal (wiring harness-side):
    • Seat warmer control unit terminal K
  • Is the voltage B+  ?
Yes Go to the next step.
No
  • Inspect the front body control module (FBCM) 1C terminal. (See FRONT BODY CONTROL MODULE (FBCM) INSPECTION ).
  • Repair or replace the open circuit at the following wiring harness.
    • Front body control module (FBCM) terminal 1C-Seat warmer control unit terminal K
7* VERIFY IF MALFUNCTION CAUSE IS SHORT TO GROUND IN SEAT WARMER CONTROL UNIT 
  • Seat warmer control unit connector on the side that is not operating is disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):
    • Seat warmer control unit terminal on the side that is not operating H-Ground
    • Seat warmer control unit terminal on the side that is not operating G-Ground
  • Is there continuity?
Yes Go to the next step.
No
  • Inspect the open circuit following.
    • Seat warmer unit terminal H-GND
    • Seat warmer unit terminal G-GND
  • Inspect the GND connector terminals for poor connection.
  • Repair or replace the malfunction.
8* VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS OF SEAT WARMER SWITCH SIGNAL 
  • Seat warmer control unit connector is disconnected.
  • Inspect for continuity between the following terminals (wiring harness-side):

    With full-auto air conditioner 

    • Seat warmer control unit terminal I-Climate control terminal 1C

    With manual air conditioner 

    • Seat warmer control unit terminal I-Clock terminal D
  • Is there continuity?
Yes Go to the next step.
No
  • Inspect the open circuit following.
    • Seat warmer control unit terminal I-Climate control terminal 1C
    • Seat warmer control unit terminal I-Clock terminal D
9* INSPECT SEAT WARMER CONTROL UNIT AND SEAT WARMER UNIT CONNECTOR 
  • Disconnect the seat warmer control unit and seat warmer unit connector on the side not operating.
  • Inspect the 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 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 P-A
    • Passenger-side seat warmer unit terminal N-B
  • Is there continuity?
Yes Go to the next step.
No Replace the seat warmer unit.
11 DETERMINE IF THE MALFUNCTION CAUSE IS SEAT WARMER CONTROL UNIT 
With full-auto air conditioner 
  • Replace the climate control unit.

With manual air conditioner 
  • Replace the clock.

  • Does the seat warmer system operate?
Yes Troubleshooting completed.
No Replace the seat warmer control unit.


DIAGNOSTIC PROCEDURE DESCRIPTION

STEP INSPECTION ACTION
1* DETERMINE IF THE MALFUNCTION CAUSE IS THE SEAT WARMER SWITCH 
  • Switch the ignition off (LOCK).

With full-auto air conditioner 
  • Disconnect the climate control unit connector.

With manual air conditioner 
  • Disconnect the clock connector.

  • Switch the ignition ON (engine off or on).
  • Is the seat warmer system operating?
Yes Go to the next step.
No Replace the climate control unit or clock.
(See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] ). (See CLOCK REMOVAL/INSTALLATION ).
2 DETERMINE IF THE MALFUNCTION CAUSE IS THE SEAT WARMER CONTROL UNIT 
  • Disconnect the seat warmer control unit connector.
  • Measure the voltage between seat warmer control unit terminal I and body ground.
  • Is the voltage 1.0 or more  ?
Yes Repair or replace for a short to ground in the wiring harness.
No Replace the seat warmer control unit. (See SEAT WARMER CONTROL UNIT REMOVAL/INSTALLATION ).


DIAGNOSTIC PROCEDURE DESCRIPTION

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 ).
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.
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.
No Replace the seat warmer control unit.