Seat Heater System: Inspection

INSPECT SEAT HEATER CONTROL SUB-ASSY

Disconnect the 3 connectors.

Inspect the seat heater control.

Fig 1: Inspecting Seat Heater Control Sub-Assy

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TERMINAL VOLTAGE SPECIFICATION

Tester condition	Connection	Specified condition
A1 <=> Body ground	Constant	Continuity
A4 <=> Body ground	Constant	10 - 14 V
A3 <=> Body ground	Seat heater switch OFF -> ON	0 V -> 10 - 14 V
A2 <=> Body ground	Seat heater switch OFF -> ON	0 V -> 10 - 14 V

If the value is not as specified, replace the seat heater control.

Connect the 3 connectors.

Inspect the seat heater control.

TERMINAL VOLTAGE SPECIFICATION

Tester condition	Connection	Specified condition
B1 <=> B2	IG ON, Seat heater switch OFF -> ON	0 V -> 10 - 14 V
C2 <=> C1	IG ON, Seat heater switch OFF -> ON	0 V -> 10 - 14 V

If the value is not as specified, replace the seat heater control.

INSPECT SEAT HEATER SWITCH

Inspect the seat heater switch continuity.

TERMINAL CONTINUITY SPECIFICATION

Condition	Tester connection	Specified condition
Constant	1 <=> 2 <=> 6 6 <=> 9 <=> 10 6 <=> 7	Continuity
ON (Driver side or Passenger side)	3 <=> 6	Continuity

If the continuity is not as specified, replace the seat heater switch.

Fig 2: Identifying Seat Heater Switch Continuity

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Inspect the seat heater switch resistance.

Fig 3: Inspecting Seat Heater Switch Resistance

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

SWITCH RESISTANCE

Tester condition	Resistance
1 <=> 6 6 <=> 10	Refer to Fig 3

If the resistance value is not as specified, replace the seat heater switch.

INSPECT FRONT SEAT BACK HEATER ASSY

Inspect the seatback heater assembly LH and RH continuity.

HEATER ASSY CONTINUITY SPECIFICATION

Condition	Tester connection	Specified condition
Constant	1 <=> 2	Continuity

If the continuity is not as specified, replace the front seatback cover assembly.

Fig 4: Identifying Seat Heater Assy Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT FRONT SEAT CUSHION HEATER ASSY

Inspect the seat cushion heater assembly LH and RH continuity.

HEATER ASSY CONTINUITY SPECIFICATION

Condition	Tester connection	Specified condition
Constant	1 <=> 2	Continuity

If the continuity is not as specified, replace the front seat cushion cover assembly.

Fig 5: Identifying Front Seat Cushion Heater Assy Connector

Inspect the seat cushion thermostat continuity.

Disconnect the seatback heater from the seat cushion heater.
Heat the thermostat with a light.
Inspect the seat cushion heater continuity between terminals, as shown in Fig 6 .

HEATER ASSY CONTINUITY SPECIFICATION

Tester connection	Condition	Specified condition
1 <=> 2	Seat heater temp. below 25 - 35<=>C (77 - 95<=>F)	Continuity
1 <=> 2	Seat heater temp. 25 - 35<=>C (77 - 95<=>F)	No continuity

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

Fig 6: Identifying Seat Heater Cushion Thermostat Connector

INSPECT SEAT HEATER CONTROL SUB-ASSY

Disconnect the 3 connectors.

Inspect the seat heater control.

HEATER ASSY CONTINUITY SPECIFICATION

Tester condition	Connection	Specified condition
1 <=> Body ground	Constant	Continuity
1 <=> 2 1 <=> 3	Seat heater switch OFF	Continuity
1 <=> 2 1 <=> 3	Seat heater switch ON	10 - 14 V
4 <=> Body ground	Constant	10 - 14 V

If the value is not as specified, replace the seat heater control.

Fig 7: Identifying Seat Heater Control Sub Assy Connector