Section 370 (Seat Heater System): Inspection

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT SEAT HEATER SWITCH CONTINUITY

SPECIFIED CONDITION

Condition	tester connection	Specified condition
OFF	-	No continuity
ON (Left)	12 - 14	Continuity
ON (Right)	14 - 16	Continuity

If continuity is not as specified replace the switch or bulb.

Fig 1: Inspecting Seat Heater Switch Continuity

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT REAR SEAT HEATER SWITCH VOLTAGE
(): Right side
1. Connect the positive (+) lead from the battery to terminal 2 and negative (-) lead terminal 8.
2. Push the switch and check the voltage between terminal 5 (7) and battery H terminal.
  If operation is not as specified, replace the switch.
  
  Fig 2: Checking Voltage Between Terminal 5 (7) And Battery H Terminal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT SEAT HEATER SWITCH CIRCUIT

Disconnect the switch connector and inspect the connector on the wire harness side, as shown.

Fig 3: Disconnecting Switch Connector And Inspect Connector On Wire Harness Side

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

SPECIFIED CONDITION

Tester connection to terminal number	Condition	Specified condition
6 - Ground	Constant	Continuity
14 - Ground	Ignition switch turned to ON	Battery positive voltage

Seat Cushion: INSPECT SEAT HEATER CONTINUITY

Heat the thermostat with a light.

Inspect the seat heater continuity between terminals.

Fig 4: Inspecting Seat Heater Continuity Between Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

SPECIFIED CONDITION

Tester connection	Condition	Specified condition
A2 - B3	Constant	Continuity
A1 - B1	Seat heater temperature bellow 25°C (77°F)	Continuity
B1 - B2	Seat heater temperature bellow 25°C (77°F)	Continuity
A1 - B2	Seat heater temperature bellow 25°C (77°F)	Continuity
A1 - B1	Seat heater temperature above 55°C (131°F)	No continuity
B1 - B2	Seat heater temperature above 45°C (113°F)	No continuity
A1 - B2	Seat heater temperature above 45°C (113°F)	No continuity

If continuity is not as specified, replace the seat cushion pad.

Seat Back: INSPECT SEAT HEATER CONTINUITY

Inspect the seat heater continuity between terminals, as shown.

Fig 5: Inspecting Seat Heater Continuity Between Terminals

SPECIFIED CONDITION

Tester connection	Condition	Specified condition
1 - 3	Constant	Continuity
2 - 3	Constant	Continuity

If continuity is not as specified, replace the seat back pad.