Lexus NX: Seat Heater for Front Right Seat does not Operate

Lexus NX Service Manual / Vehicle Interior / Seat / Seat Heater System / Seat Heater for Front Right Seat does not Operate

DESCRIPTION

When the seat heater switch on air conditioning control assembly is operated, the air conditioning amplifier assembly receives the signal. The air conditioning amplifier assembly receives the signal and operates the front seat heater.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the auxiliary battery voltage is low, the seat heater system may not operate. When "High Power Consumption / Partial Limit On AC/Heater Operation" is displayed on the multi-information display in the combination meter assembly, inspect the auxiliary battery, referring to On-vehicle Inspection for the charging system.

    Click here

    HINT:

    If the auxiliary battery voltage is low, "Operation Limitation Control History Count (Level 1)" and "Operation Limitation Control History Count (Level 2) is counted.

    Click here

  • If the auxiliary battery voltage is low, the seat heater system may not operate. Refer to Data List for the power steering system.

    for Manual Tilt and Manual Telescopic Steering Column: Click here

    for Power Tilt and Power Telescopic Steering Column: Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (FR Seat Heater Temperature)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

FR Seat Heater Temperature

Front seat RH heater temperature

-29.7°C to 59.55°C

Within range from 32 to 43°C (89 to 109°F)

Front seat heater is on

Body Electrical > Air Conditioner > Data List

Tester Display

FR Seat Heater Temperature

OK:

On the Techstream screen, the seat heater temperature is as specified in the normal condition column.

OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

2.

CHECK HARNESS AND CONNECTOR (SEAT HEATER CONTROL SUB-ASSEMBLY RH - BATTERY AND BODY GROUND)

(a) Disconnect the seat heater control sub-assembly RH connector.

*a

Front view of wire harness connector

(to Seat Heater Control Sub-assembly RH)

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

f9-6 (E) - Body ground

Always

Below 1 Ω

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

f9-4 (IG) - Body ground

Power switch on (IG)

11 to 14 V

f9-4 (IG) - Body ground

Power switch off

Below 1 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

INSPECT SEAT HEATER CONTROL SUB-ASSEMBLY RH

(a) Disconnect the f9 and SHR seat heater control sub-assembly RH connectors.

*a

Seat Heater Control Sub-assembly RH

(to Air Conditioning Amplifier Assembly)

*b

Seat Heater Control Sub-assembly RH

(to Separate Type Front Seat Cushion Cover RH)

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

f9-5 (THR) - SHR-2 (TH1)

Always

Below 1 Ω

f9-5 (THR) or SHR-2 (TH1) - Body ground

Always

10 kΩ or higher

f9-2 (PR) - SHR-3 (TH2)

Always

Below 1 Ω

f9-2 (PR) or SHR-3 (TH2) - Body ground

Always

10 kΩ or higher

NG

REPLACE SEAT HEATER CONTROL SUB-ASSEMBLY RH

OK

4.

INSPECT SEPARATE TYPE FRONT SEAT CUSHION COVER RH

(a) Remove the separate type front seat cushion cover RH.

Click here

(b) Inspect the separate type front seat cushion cover RH.

Click here

NG

REPLACE SEPARATE TYPE FRONT SEAT CUSHION COVER RH

OK

5.

INSPECT SEPARATE TYPE FRONT SEATBACK COVER RH

(a) Remove the separate type front seatback cover RH.

Click here

(b) Inspect the separate type front seatback cover RH.

Click here

NG

REPLACE SEPARATE TYPE FRONT SEATBACK COVER RH

OK

6.

CHECK SEAT HEATER CONTROL SUB-ASSEMBLY RH

(a) Temporarily replace the seat heater control sub-assembly RH with a new or known good one.

for Front Seat: Click here

for Rear Seat: Click here

(b) Check that the seat heater system is operated normally.

OK:

The seat heater system is operated normally.

OK

END (SEAT HEATER CONTROL SUB-ASSEMBLY RH WAS DEFECTIVE)

NG

7.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - SEAT HEATER CONTROL SUB-ASSEMBLY RH)

(a) Disconnect the I50 and I54 air conditioning amplifier assembly connectors.

(b) Disconnect the f9 seat heater control sub-assembly RH connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

I50-16 (SHP+) - f9-1 (SWR)

Always

Below 1 Ω

I50-16 (SHP+) or f9-1 (SWR) - Body ground

Always

10 kΩ or higher

I54-3 (TSR) - f9-5 (THR)

Always

Below 1 Ω

I54-3 (TSR) or f9-5 (THR) - Body ground

Always

10 kΩ or higher

I54-7 (SG-3) - f9-2 (PR)

Always

Below 1 Ω

I54-7 (SG-3) or f9-2 (PR) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Temporarily replace the air conditioning amplifier assembly with a new or known good one.

Click here

(b) Check that the seat heater system is operated normally.

OK:

The seat heater system is operated normally.

OK

END (AIR CONDITIONING AMPLIFIER ASSEMBLY WAS DEFECTIVE)

NG

REPLACE AIR CONDITIONING CONTROL ASSEMBLY

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 Transmission Control Switch Circuit

DESCRIPTION When the shift lever is in S, different ranges can be chosen using the floor shift sequential gate. WIRING DIAGRAM PROCEDURE 1. READ VALUE USING TECHSTREAM (SPORTS MODE) (a) Connect the Techstream to the DLC3. (b) Turn the power switch on (IG). (c) Enter the following menus: Po

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