DESCRIPTION
When the refreshing seat switch (for front side) 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:
Click here
Click here
PROCEDURE
1. | CLEAR DTC |
(a) Clear the DTCs.
Click here
|
2. | CHECK FOR DTC |
(a) Check for DTCs.
Click here
OK:
DTC B14B5 or B14C1 is not output.
Result | Proceed to |
---|---|
OK (for Standard Seat Type) | A |
OK (for Sports Seat Type) | B |
NG | C |
B | ![]() | GO TO STEP 7 |
C | ![]() | GO TO DIAGNOSTIC TROUBLE CODE CHART |
|
3. | CHECK HARNESS AND CONNECTOR (IG POWER SUPPLY - FRONT SEAT CUSHION HEATER LH (SEAT HEATER ASSEMBLY) - BODY GROUND) |
(a) Disconnect the c8 front seat cushion heater LH (seat heater assembly) connector. |
|
(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard Voltage:
Tester Connection | Condition | Specified Condition |
---|---|---|
c8-3 (IG) - Body ground | Engine switch on (IG) | 11 to 14 V |
c8-3 (IG) - Body ground | Engine switch off | Below 1 V |
c8-1 (B) - Body ground | Always | 11 to 14 V |
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
c8-2 (E) - Body ground | Always | Below 1 Ω |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
4. | INSPECT FRONT SEAT CUSHION HEATER LH (SEAT HEATER ASSEMBLY) |
(a) Remove the front seat cushion heater LH (seat heater assembly).
Click here
(b) Inspect the front seat cushion heater LH (seat heater assembly).
Click here
NG | ![]() | REPLACE FRONT SEAT CUSHION HEATER LH (SEAT HEATER ASSEMBLY) |
|
5. | INSPECT FRONT SEATBACK HEATER LH (SEAT HEATER ASSEMBLY) |
(a) Remove the front seatback heater LH (seat heater assembly).
Click here
(b) Inspect the front seatback heater LH (seat heater assembly).
Click here
NG | ![]() | REPLACE FRONT SEATBACK HEATER LH (SEAT HEATER ASSEMBLY) |
|
6. | CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - FRONT SEAT CUSHION HEATER LH (SEAT HEATER ASSEMBLY)) |
(a) Disconnect the J42 and J48 air conditioning amplifier assembly connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
J48-15 (SHD+) - c8-5 (SWR) | Always | Below 1 Ω |
J48-15 (SHD+) or c8-5 (SWR) - Body ground | Always | 10 kΩ or higher |
J48-17 (TSL) - c8-6 (THR) | Always | Below 1 Ω |
J48-17 (TSL) or c8-6 (THR) - Body ground | Always | 10 kΩ or higher |
J42-8 (SG-5) - c8-4 (PR) | Always | Below 1 Ω |
J42-8 (SG-5) or c8-4 (PR) - Body ground | Always | 10 kΩ or higher |
OK | ![]() | GO TO STEP 11 |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
7. | CHECK HARNESS AND CONNECTOR (IG POWER SUPPLY - FRONT SEAT CUSHION HEATER (FRONT SEAT CUSHION PAD WITH COVER LH) - BODY GROUND) |
(a) Disconnect the c8 front seat cushion heater (front seat cushion pad with cover LH) connector. |
|
(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard Voltage:
Tester Connection | Condition | Specified Condition |
---|---|---|
c8-3 (IG) - Body ground | Engine switch on (IG) | 11 to 14 V |
c8-3 (IG) - Body ground | Engine switch off | Below 1 V |
c8-1 (B) - Body ground | Always | 11 to 14 V |
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
c8-2 (E) - Body ground | Always | Below 1 Ω |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
8. | INSPECT FRONT SEAT CUSHION HEATER (FRONT SEAT CUSHION PAD WITH COVER LH) |
(a) Remove the front seat cushion heater (front seat cushion pad with cover LH).
Click here
(b) Inspect the front seat cushion heater (front seat cushion pad with cover LH).
Click here
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
9. | INSPECT FRONT SEATBACK HEATER (FRONT SEATBACK PAD WITH COVER LH) |
(a) Remove the front seatback heater (front seatback pad with cover LH).
Click here
(b) Inspect the front seatback heater (front seatback pad with cover LH).
Click here
NG | ![]() | REPLACE FRONT SEATBACK HEATER (FRONT SEATBACK PAD WITH COVER LH) |
|
10. | CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - FRONT SEAT CUSHION HEATER (FRONT SEAT CUSHION PAD WITH COVER LH)) |
(a) Disconnect the J42 and J48 air conditioning amplifier assembly connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection | Condition | Specified Condition |
---|---|---|
J48-15 (SHD+) - c8-5 (SWR) | Always | Below 1 Ω |
J48-15 (SHD+) or c8-5 (SWR) - Body ground | Always | 10 kΩ or higher |
J48-17 (TSL) - c8-6 (THR) | Always | Below 1 Ω |
J48-17 (TSL) or c8-6 (THR) - Body ground | Always | 10 kΩ or higher |
J42-8 (SG-5) - c8-4 (PR) | Always | Below 1 Ω |
J42-8 (SG-5) or c8-4 (PR) - Body ground | Always | 10 kΩ or higher |
NG | ![]() | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
11. | REPLACE SEAT HEATER CONTROL SUB-ASSEMBLY LH |
(a) Temporarily replace the seat heater control sub-assembly LH with a new or known good one.
Click here
|
12. | CHECK SEAT HEATER OPERATION |
(a) Check the seat heater.
Click here
OK:
The seat heater operates normally.
OK | ![]() | END (SEAT HEATER CONTROL SUB-ASSEMBLY LH WAS DEFECTIVE) |
|
13. | REPLACE REFRESHING SEAT SWITCH (FOR FRONT SIDE) |
(a) Temporarily replace the refreshing seat switch (for front side) with a new or known good one.
Click here
|
14. | CHECK SEAT HEATER OPERATION |
(a) Check the seat heater.
Click here
OK:
The seat heater operates normally.
OK | ![]() | END (REFRESHING SEAT SWITCH (FOR FRONT SIDE) WAS DEFECTIVE) |
NG | ![]() | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Front Seat Side Airbag Assembly: Components
COMPONENTS ILLUSTRATION *A for Standard Seat Type *B for Sports Seat Type *1 FRONT SEAT AIRBAG ASSEMBLY *2 FRONT SEAT CUSHION SHIELD *3 FRONT SEAT HEADREST SUPPORT *4 FRONT SEAT INNER CUSHION SHIELD *5 FRONT SEATBACK BOARD SUB-ASSEMBLY *6 FRONT SEATBACK PAD WI ...
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Seat Heater System: Lost Communication with Front Seat Temperature Adjustment Switch LIN (B14B5)
DESCRIPTION The refreshing seat switch (for front side) communicates with the air conditioning amplifier assembly via LIN communication. If the LIN communication system is malfunctioning, the air conditioning amplifier assembly will not operate even if the refreshing seat switch (for front side) is ...