Seat Heater System: Inspection

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT FRONT SEAT CUSHION HEATER ASSY RH

Inspect the seat cushion thermostat continuity.

Disconnect the seat back heater from the seat cushion heater.
Heat the temperature sensor and thermostat with a light.

Inspect the seat cushion heater continuity between terminals, as shown.

Fig 1: Identifying Front Seat Cushion Heater Assy RH Connector Terminal

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard:

FRONT SEAT CUSHION HEATER ASSY RH TERMINAL SPECIFICATION

Terminal No.	Condition	Specified condition
S20-1 <=> 2	Seat heater temp. below 25 - 35 °C (77 - 95 °F)	8,000 - 8,400 Ω
S20-1 <=> 2	Seat heater temp. 46 - 54 °C (115 - 129 °F)	3,900 - 4,300 Ω
S20-3 <=> 1	Seat heater temp. below 25 - 35 °C (77 - 95 °F)	Continuity
S20-3 <=> 1	Seat heater temp. 46 - 54 °C (115 - 129 °F)	No continuity (thermostat OFF)
S20-3 <=> 2	Seat heater temp. below 25 - 35 °C (77 - 95 °F)	Continuity
S20-3 <=> 2	Seat heater temp. 46 - 54 °C (115 - 129 °F)	No continuity (thermostat OFF)
S20-4 <=> 1	Constant	Continuity

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

INSPECT FRONT SEAT CUSHION HEATER ASSY LH

Inspect the seat cushion thermostat continuity.

Disconnect the seat back heater from the seat cushion heater.
Heat the temperature sensor and thermostat with a light.

Inspect the seat cushion heater continuity between terminals, as shown.

Fig 2: Identifying Front Seat Cushion Heater Assy LH Connector Terminal

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard:

FRONT SEAT CUSHION HEATER ASSY LH TERMINAL SPECIFIED CONDITION CHART

Terminal No.	Condition	Specified condition
S22-1 <=> 2	Seat heater temp. below 25 - 35 °C (77 - 95 °F)	8,000 - 8,400 Ω
S22-1 <=> 2	Seat heater temp. 46 - 54 °C (115 - 129 °F)	3,900 - 4,300 Ω
S22-3 <=> 1	Seat heater temp. below 25 - 35 °C (77 - 95 °F)	Continuity
S22-3 <=> 1	Seat heater temp. 46 - 54 °C (115 - 129 °F)	No continuity (thermostat OFF)
S22-3 <=> 2	Seat heater temp. below 25 - 35 °C (77 - 95 °F)	Continuity
S22-3 <=> 2	Seat heater temp. 46 - 54 °C (115 - 129 °F)	No continuity (thermostat OFF)
S22-4 <=> 1	Constant	Continuity

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

INSPECT FRONT SEAT BACK HEATER ASSY RH

Inspect the seatback heater assembly RH continuity.

Standard:

FRONT SEAT BACK HEATER ASSY RH TERMINAL SPECIFIED CONDITION CHART

Terminal No.	Condition	Specified condition
1 - 2	Constant	Continuity

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

Fig 3: Identifying Front Seat Back Heater Assy RH Connector Terminal

INSPECT FRONT SEAT BACK HEATER ASSY LH

Inspect the seatback heater assembly LH continuity.

Standard:

FRONT SEAT BACK HEATER ASSY LH TERMINAL SPECIFIED CONDITION CHART

Terminal No.	Condition	Specified condition
1 - 2	Constant	Continuity

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

Fig 4: Identifying Front Seat Back Heater Assy LH Connector Terminal