Seat Temperature Element: Testing and Inspection

INSPECTION

1. WIRING DIAGRAM
Refer to "Seat Heater System" in the wiring diagram. [Ref. to WIRING DIAGRAM, Seat Heater System.] Electrical Diagrams

2. DIAGNOSTIC CHART







3. CHECK SEAT HEATER FUSE
Remove the seat heater fuse and inspect visually.
Is the fuse blown out?
- Yes -> Replace the fuse.
- No -> Check the power supply and ground circuits.

4. CHECK SEAT HEATER RELAY
1. Remove the seat heater relay from the relay holder.
2. Measure the resistance between seat heater relay terminals.

Preparation tool: Circuit tester







3. Replace the seat heater relay if the inspection result is not within the standard value.

5. CHECK SEAT HEATER SWITCH

1. CHECK SEAT HEATER SWITCH
1. Turn the ignition switch to ON.
2. Measure the voltage between the seat heater switch and chassis ground when turning the switch a position other than OFF.

Connector & terminal
LHD side seat
(R42) No. 4 (+) - Chassis ground (-):
RHD side seat
(R45) No. 4 (+) - Chassis ground (-):

Does the voltage fluctuate between 12 V from/to 0 V?
- Yes -> Harness faulty, open circuit of heater or thermostat faulty.
- No -> Replace the seat heater switch.

6. CHECK POWER SUPPLY AND GROUND CIRCUIT

1. CHECK POWER SUPPLY CIRCUIT.
1. Disconnect the seat heater switch.
2. Turn the ignition switch to ON.
3. Measure the voltage between harness connector terminal and chassis ground.

Connector & terminal
Driver's side
(R42) No. 4 (+) - Chassis ground (-):
Passenger's side
(R45) No. 4 (+) - Chassis ground (-):

Is the voltage 12 V or more?
- Yes -> Go to step 2.
- No -> Check the harness between the seat heater switch and fuse.

2. CHECK GROUND CIRCUIT.
Measure the resistance between harness connector terminal and chassis ground.

Connector & terminal
Driver seat (manual seat)
(R42) No. 6 - Chassis ground:
(R41) No. 1 - Chassis ground:
Passenger seat (manual seat)
(R45) No. 6 - Chassis ground:
(R44) No. 1 - Chassis ground:
Driver seat (power seat)
(R42) No. 6 - Chassis ground:
(R380) No. 1 - Chassis ground:
Passenger seat (power seat)
(R45) No. 6 - Chassis ground:
(R363) No. 1 - Chassis ground:

Is the resistance less than 10 ohm?
- Yes -> The power supply and ground circuits are normal.
- No -> Repair the harness.