Climate Control Seat (Diagnostics): Overview Lexus ES XV40 facelift

SYSTEM DESCRIPTION

1. GENERAL The blower volume has 4 levels controlled by operating the dial-type climate control seat switch, which is located in the console box. Whether the blower is ON or OFF can be determined by checking if the climate control seat switch indicator light is ON or OFF. The blowers of both seats are controlled by the air conditioning amplifier assembly (A/C ECU).

DESCRIPTION

The A/C amplifier assembly receives seat position signals when the engine switch is on (IG), and then transmits airflow amount signals to each seat climate blower.

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1. SYSTEM CHECK Check if the climate control seat system operates normally. Result Result Proceed to Climate control does not operate on driver side A Climate control does not operate on front passenger side B Climate control does not operate on both driver and front passenger sides C C --> See step 14 B --> See step 8 A: Go to next step
2. CHECK WIRE HARNESS Disconnect the U15 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition U15-4 (GND) - Body ground Always Below 1 ohms Standard voltage Tester Connection Condition Specified Condition U15-1 (IG) - Body ground Engine switch on (IG) 10 to 14 V Reconnect the U15 connector. Disconnect the U14 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition U14-1 (GND) - Body ground Always Below 1 ohms Standard voltage Tester Connection Condition Specified Condition U14-2 (IG) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
3. INSPECT SEAT CLIMATE CONTROL BLOWER Check the input signal waveform. Connect an oscilloscope to terminal U15-3 (SIGN) and body ground with the climate control blower connector still connected. Check the signal waveform according to the condition(s) in the table below. Item Condition Tool setting 2 V/DIV., 500 μsec/DIV. Vehicle condition Engine switch on (IG), seat heater switch ON OK The waveform is displayed as shown in the illustration. Result Result Proceed to NG A OK (Seat cushion blower side) B OK (Seatback blower side) C C --> REPLACE SEATBACK BLOWER B --> REPLACE SEAT CUSHION BLOWER A: Go to next step
4. CHECK WIRE HARNESS (A/C AMPLIFIER ASSEMBLY - SEAT CLIMATE CONTROL BLOWER) Disconnect the E2 and U15 connectors. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E2-9 (SVDB) - U15-3 (SIGN) Always Below 1 ohms E2-9 (SVDB) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
5. CHECK WIRE HARNESS (SEAT HEATER SWITCH) Disconnect the F3 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition F3-12 (E) - Body ground Always Below 1 ohms Standard voltage Tester Connection Condition Specified Condition F3-5 (IG) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
6. INSPECT SEAT HEATER SWITCH Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition F3-7 (BLLH) - F3-10 (SVSG) Blower switch OFF 0.77 to 1.43 kohms Blower switch ON (Vol: 3) 110 to 270 ohms F3-8 (SVS5) - F3-10 (SVSG) Always 0.77 to 1.43 kohms NG --> REPLACE SEAT HEATER SWITCH OK: Go to next step
7. CHECK WIRE HARNESS (SEAT HEATER SWITCH - A/C AMPLIFIER ASSEMBLY) Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition F3-7 (BLLH) - E2-15 (SVDS) Always Below 1 ohms F3-8 (SVS5) - E2-8 (S5-2) Always Below 1 ohms F3-10 (SVSG) - E2-6 (SG-5) Always Below 1 ohms F3-12 (E) - Body ground Always Below 1 ohms F3-7 (BLLH) - Body ground Always 10 kohms or higher F3-8 (SVS5) - Body ground Always 10 kohms or higher F3-10 (SVSG) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE WIRE HARNESS OK --> REPLACE A/C AMPLIFIER ASSEMBLY
8. CHECK WIRE HARNESS Disconnect the T17 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition T17-4 (GND) - Body ground Always Below 1 ohms Standard voltage Tester Connection Condition Specified Condition T17-1 (IG) - Body ground Engine switch on (IG) 10 to 14 V Reconnect the T17 connector. Disconnect the T16 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition T16-1 (GND) - Body ground Always Below 1 ohms Standard voltage Tester Connection Condition Specified Condition T16-2 (IG) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
9. INSPECT SEAT CLIMATE CONTROL BLOWER Check the input signal waveform. Connect an oscilloscope to terminal T17-3 (SIGN) and body ground with the climate control blower connector still connected. Check the signal waveform according to the condition(s) in the table below. Item Condition Tool setting 2 V/DIV., 500 μsec/DIV. Vehicle condition Engine switch on (IG), seat heater switch ON OK The waveform is displayed as shown in the illustration. Result Result Proceed to NG A OK (Seat cushion blower side) B OK (Seatback blower side) C C --> REPLACE SEATBACK BLOWER B --> REPLACE SEAT CUSHION BLOWER A: Go to next step
10. CHECK WIRE HARNESS (A/C AMPLIFIER ASSEMBLY - SEAT CLIMATE CONTROL BLOWER) Disconnect the E2 and T17 connectors. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition E2-10 (SVPB) - T17-3 (SIGN) Always Below 1 ohms E2-10 (SVPB) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
11. CHECK WIRE HARNESS (SEAT HEATER SWITCH) Disconnect the F3 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition F3-12 (E) - Body ground Always Below 1 ohms Standard voltage Tester Connection Condition Specified Condition F3-5 (IG) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
12. INSPECT SEAT HEATER SWITCH Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition F3-10 (SVSG) - F3-9 (BLRH) Blower switch OFF 0.77 to 1.43 kohms Blower switch ON (Vol: 3) 110 to 270 ohms F3-8 (SVS5) - F3-10 (SVSG) Always 0.77 to 1.43 kohms NG --> REPLACE SEAT HEATER SWITCH OK: Go to next step
13. CHECK WIRE HARNESS (SEAT HEATER SWITCH - A/C AMPLIFIER ASSEMBLY) Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition F3-8 (SVS5) - E2-8 (S5-2) Always Below 1 ohms F3-9 (BLRH) - E2-16 (SVPS) Always Below 1 ohms F3-10 (SVSG) - E2-6 (SG-5) Always Below 1 ohms F3-12 (E) - Body ground Always Below 1 ohms F3-8 (SVS5) - Body ground Always 10 kohms or higher F3-9 (BLRH) - Body ground Always 10 kohms or higher F3-10 (SVSG) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE WIRE HARNESS OK --> REPLACE A/C AMPLIFIER ASSEMBLY
14. CHECK WIRE HARNESS Disconnect the U15 and T17 connectors. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Front LH Front RH Tester Connection Condition Specified Condition U15-4 (GND) - Body ground Always Below 1 ohms Tester Connection Condition Specified Condition T17-4 (GND) - Body ground Always Below 1 ohms Standard voltage Front LH Front RH Tester Connection Condition Specified Condition U15-1 (IG) - Body ground Engine switch on (IG) 10 to 14 V Tester Connection Condition Specified Condition T17-1 (IG) - Body ground Engine switch on (IG) 10 to 14 V Reconnect the U15 and T17 connectors. Disconnect the U14 and T16 connectors. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Front LH Front RH Tester Connection Condition Specified Condition U14-1 (GND) - Body ground Always Below 1 ohms Tester Connection Condition Specified Condition T16-1 (GND) - Body ground Always Below 1 ohms Standard voltage Front LH Front RH Tester Connection Condition Specified Condition U14-2 (IG) - Body ground Engine switch on (IG) 10 to 14 V Tester Connection Condition Specified Condition T16-2 (IG) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
15. INSPECT SEAT CLIMATE CONTROL BLOWER Check the input signal waveform. Connect an oscilloscope to terminal 3 and body ground with the climate control blower connector still connected. Check the signal waveform according to the condition(s) in the table below. Item Condition Tool setting 2 V/DIV., 500 μsec/DIV. Vehicle condition Engine switch on (IG), seat heater switch ON OK The waveform is displayed as shown in the illustration. Result Result Proceed to NG A OK (Seat cushion blower side) B OK (Seatback blower side) C C --> REPLACE SEATBACK BLOWER B --> REPLACE SEAT CUSHION BLOWER A: Go to next step
16. CHECK WIRE HARNESS (A/C AMPLIFIER ASSEMBLY - SEAT CLIMATE CONTROL BLOWER) Disconnect the E2, U15 and T17 connectors. Measure the resistance according to the value(s) in the table below. Standard resistance Front LH Front RH Tester Connection Condition Specified Condition E2-9 (SVDB) - U15-3 (SIGN) Always Below 1 ohms E2-9 (SVDB) - Body ground Always 10 kohms or higher Tester Connection Condition Specified Condition E2-10 (SVPB) - T17-3 (SIGN) Always Below 1 ohms E2-10 (SVPB) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
17. CHECK WIRE HARNESS (SEAT HEATER SWITCH) Disconnect the F3 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard resistance Tester Connection Condition Specified Condition F3-12 (E) - Body ground Always Below 1 ohms Standard voltage Tester Connection Condition Specified Condition F3-5 (IG) - Body ground Engine switch on (IG) 10 to 14 V NG --> REPAIR OR REPLACE WIRE HARNESS OK: Go to next step
18. INSPECT SEAT HEATER SWITCH Measure the resistance according to the value(s) in the table below. Standard resistance Front LH Front RH Tester Connection Condition Specified Condition F3-7 (BLLH) - F3-10 (SVSG) Blower switch OFF 0.77 to 1.43 kohms Blower switch ON (Vol: 3) 110 to 270 ohms F3-8 (SVS5) - F3-10 (SVSG) Always 0.77 to 1.43 kohms Tester Connection Condition Specified Condition F3-10 (SVSG) - F3-9 (BLRH) Blower switch OFF 0.77 to 1.43 kohms Blower switch ON (Vol: 3) 110 to 270 ohms F3-8 (SVS5) - F3-10 (SVSG) Always 0.77 to 1.43 kohms NG --> REPLACE SEAT HEATER SWITCH OK: Go to next step
19. CHECK WIRE HARNESS (SEAT HEATER SWITCH - A/C AMPLIFIER ASSEMBLY) Measure the resistance according to the value(s) in the table below. Standard resistance Front LH Front RH Tester Connection Condition Specified Condition F3-7 (BLLH) - E2-15 (SVDS) Always Below 1 ohms F3-8 (SVS5) - E2-8 (S5-2) Always Below 1 ohms F3-10 (SVSG) - E2-6 (SG-5) Always Below 1 ohms F3-12 (E) - Body ground Always Below 1 ohms F3-7 (BLLH) - Body ground Always 10 kohms or higher F3-8 (SVS5) - Body ground Always 10 kohms or higher F3-10 (SVSG) - Body ground Always 10 kohms or higher Tester Connection Condition Specified Condition F3-8 (SVS5) - E2-8 (S5-2) Always Below 1 ohms F3-9 (BLRH) - E2-16 (SVPS) Always Below 1 ohms F3-10 (SVSG) - E2-6 (SG-5) Always Below 1 ohms F3-12 (E) - Body ground Always Below 1 ohms F3-8 (SVS5) - Body ground Always 10 kohms or higher F3-9 (BLRH) - Body ground Always 10 kohms or higher F3-10 (SVSG) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE WIRE HARNESS OK --> REPLACE A/C AMPLIFIER ASSEMBLY