Check Power Supply And Ground 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 seat 

(R42) No. 4 (+) - Chassis ground (-): 

Passenger's seat 

(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.

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 Ω?

• Yes  → The power supply and ground circuits are normal.
• No  → Repair the harness.