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Climate Control Seat (Diagnostics): Overview Lexus RX III

Seats 17 illustrations ~1979 words

SYSTEM DESCRIPTION

  1. GENERAL The blower volume has 3 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 heater switch position signals when the engine switch is on (IG), and then transmits airflow amount signals to each seat climate blower.

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Scheme 103: WIRING DIAGRAM
Scheme 103: WIRING DIAGRAM

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Scheme 104: PROCEDURE
Scheme 104: PROCEDURE

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  1. SYSTEM CHECK Check the climate control seat operation. Result Result Proceed to Climate control seat does not operate (Front LH) A Climate control seat does not operate (Front RH) B Both climate control seats do not operate C C --> See step 18 B --> See step 10 A: Go to next step
  2. SYSTEM CHECK Check the climate control operation again. Result Result Proceed to Only seat back climate control blower LH does not operate A Both climate control blower do not operate B B --> See step 5 A: Go to next step
  3. CHECK HARNESS AND CONNECTOR Disconnect the a16 connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition a16-2 (IG) - a16-1 (GND) Engine switch on (IG) Blower switch ON (Vol: 1 to 3) 6.7 to 9.3 V TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Back Climate Control Blower LH) NG --> See step 4 OK --> See step 20
  4. CHECK HARNESS AND CONNECTOR Disconnect the a15 connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition a16-2 (IG) - a15-2 (CTB) Always Below 1 ohms a16-2 (IG) - Body ground Always 10 kohms or higher a16-1 (GND) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Cushion Climate Control Blower Assembly LH) *2 Front view of wire harness connector (to Seat Back Climate Control Blower LH) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 21
  5. CHECK HARNESS AND CONNECTOR Disconnect the a15 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard Voltage and Resistance Tester Connection Condition Specified Condition a15-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V a15-4 (GND) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Cushion Climate Control Blower Assembly LH) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
  6. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY Reconnect the a15 connector. Check the input signal waveform. Connect the oscilloscope to terminal 3 and body ground with the seat cushion climate control blower assembly LH connector still connected. Check the signal waveform according to the condition(s) in the table below. Terminal No. a15-3 (SIGN) - Body ground Tool Setting 2 V/DIV., 500 μsec./DIV. Vehicle Condition Engine switch on (IG), seat hater switch ON TEXT IN ILLUSTRATION *1 Component with harness connected (Seat Cushion Climate Control Blower Assembly LH) NG --> See step 7 OK --> See step 22
  7. CHECK HARNESS AND CONNECTOR Disconnect the a15 and F51 connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition a15-3 (SIGN) - F51-9 (SVDB) Always Below 1 ohms a15-3 (SIGN) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Cushion Climate Control Blower Assembly LH) *2 Front view of wire harness connector (to A/C amplifier Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
  8. INSPECT SEAT HEATER SWITCH Remove the seat heater switch. Refer to «REMOVAL»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F34-8 (SVS5) - F34-10 (SVSG) Always 1.54 to 2.86 kohms F34-7 (BLLH) - F34-10 (SVSG) Blower switch OFF 1.54 to 2.86 kohms F34-7 (BLLH) - F34-10 (SVSG) Blower switch ON (Vol: 3) Below 1 to 100 ohms TEXT IN ILLUSTRATION *1 Component without harness connected (Seat Heater Switch) NG --> See step 23 OK: Go to next step
  9. CHECK HARNESS AND CONNECTOR Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F34-7 (BLLH) - F51-15 (SVDS) Always Below 1 ohms F34-8 (SVS5) - F51-8 (S5-2) Always Below 1 ohms F34-10 (SVSG) - F51-6 (SG-5) Always Below 1 ohms F34-7 (BLLH) - Body ground Always 10 kohms or higher F34-8 (SVS5) - Body ground Always 10 kohms or higher F34-10 (SVSG) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Heater Switch) *2 Front view of wire harness connector (to A/C Amplifier Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 24
  10. SYSTEM CHECK Check the climate control operation again. Result Result Proceed to Only seat back climate control blower RH does not operate A Both climate control blower do not operate B B --> See step 13 A: Go to next step
  11. CHECK HARNESS AND CONNECTOR Disconnect the Z20 connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition Z20-2 (IG) - Z20-1 (GND) Engine switch on (IG) Blower switch ON (Vol: 1 to 3) 6.7 to 9.3 V TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Back Climate Control Blower RH) NG --> See step 12 OK --> See step 25
  12. CHECK HARNESS AND CONNECTOR Disconnect the Z19 connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Z20-2 (IG) - Z19-2 (CTB) Always Below 1 ohms Z20-2 (IG) - Body ground Always 10 kohms or higher Z20-1 (GND) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Cushion Climate Control Blower Assembly RH) *2 Front view of wire harness connector (to Seat Back Climate Control Blower RH) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 26
  13. CHECK HARNESS AND CONNECTOR Disconnect the Z19 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard Voltage and Resistance Tester Connection Condition Specified Condition Z19-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V Z19-4 (GND) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Cushion Climate Control Blower Assembly RH) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
  14. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY Reconnect the Z19 connector. Check the input signal waveform. Connect the oscilloscope to terminal 3 and body ground with the climate control blower assembly RH connector still connected. Check the signal waveform according to the condition(s) in the table below. Terminal No. Z19-3 (SIGN) - Body ground Tool Setting 2 V/DIV., 500 μsec./DIV. Vehicle Condition Engine switch on (IG), seat heater switch ON TEXT IN ILLUSTRATION *1 Component with harness connected (Seat Cushion Climate Control Blower Assembly RH) NG --> See step 15 OK --> See step 27
  15. CHECK HARNESS AND CONNECTOR Disconnect the Z19 and F51 connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Z19-3 (SIGN) - F51-10 (SVPB) Always Below 1 ohms Z19-3 (SIGN) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Cushion Climate Control Blower Assembly RH) *2 Front view or wire harness connector (to A/C Amplifier Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
  16. INSPECT SEAT HEATER SWITCH Remove the seat heater switch. Refer to «REMOVAL»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F34-8 (SVS5) - F34-10 (SVSG) Always 1.54 to 2.86 kohms F34-9 (BLRH) - F34-10 (SVSG) Blower switch OFF 1.54 to 2.86 kohms F34-9 (BLRH) - F34-10 (SVSG) Blower switch ON (Vol: 3) Below 1 to 100 ohms TEXT IN ILLUSTRATION *1 Component without harness connected (Seat Heater Switch) NG --> See step 28 OK: Go to next step
  17. CHECK HARNESS AND CONNECTOR Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F34-9 (BLRH) - F51-16 (SVPS) Always Below 1 ohms F34-8 (SVS5) - F51-8 (S5-2) Always Below 1 ohms F34-10 (SVSG) - F51-6 (SG-5) Always Below 1 ohms F34-12 (E) - Body ground Always Below 1 ohms F34-9 (BLRH) - Body ground Always 10 kohms or higher F34-8 (SVS5) - Body ground Always 10 kohms or higher F34-10 (SVSG) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Heater Switch) *2 Front view of wire harness connector (to A/C Amplifier Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 29
  18. INSPECT SEAT HEATER SWITCH Remove the seat heater switch. Refer to «REMOVAL»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F34-8 (SVS5) - F34-10 (SVSG) Always 1.54 to 2.86 kohms F34-7 (BLLH) - F34-10 (SVSG) Blower switch OFF 1.54 to 2.86 kohms F34-7 (BLLH) - F34-10 (SVSG) Blower switch ON (Vol: 3) Below 1 to 100 ohms F34-9 (BLRH) - F34-10 (SVSG) Blower switch OFF 1.54 to 2.86 kohms F34-9 (BLRH) - F34-10 (SVSG) Blower switch ON (Vol: 3) Below 1 to 100 ohms TEXT IN ILLUSTRATION *1 Component without harness connected (Seat Heater Switch) NG --> See step 30 OK: Go to next step
  19. CHECK HARNESS AND CONNECTOR Disconnect the F51 connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F34-7 (BLLH) - F51-15 (SVDS) Always Below 1 ohms F34-8 (SVS5) - F51-8 (S5-2) Always Below 1 ohms F34-9 (BLRH) - F51-16 (SVPS) Always Below 1 ohms F34-10 (SVSG) - F51-6 (SG-5) Always Below 1 ohms F34-7 (BLLH) - Body ground Always 10 kohms or higher F34-8 (SVS5) - Body ground Always 10 kohms or higher F34-9 (BLRH) - Body ground Always 10 kohms or higher F34-10 (SVSG) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 Front view of wire harness connector (to Seat Heater Switch) *2 Front view of wire harness connector (to A/C Amplifier Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 31
  20. REPLACE SEAT BACK CLIMATE CONTROL BLOWER LH. Refer to «DISASSEMBLY - Step 25»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  21. REPLACE SEAT CUSHION CLIMATE CONTROL BLOWER ASSEMBLY LH. Refer to «DISASSEMBLY - Step 36»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  22. REPLACE SEAT CUSHION CLIMATE CONTROL BLOWER ASSEMBLY LH. Refer to «DISASSEMBLY - Step 36»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  23. REPLACE SEAT HEATER SWITCH. Refer to «REMOVAL»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  24. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»
  25. REPLACE SEAT BACK CLIMATE CONTROL BLOWER RH. Refer to «DISASSEMBLY - Step 25»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  26. REPLACE SEAT CUSHION CLIMATE CONTROL BLOWER ASSEMBLY RH. Refer to «DISASSEMBLY - Step 25»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  27. REPLACE SEAT CUSHION CLIMATE CONTROL BLOWER ASSEMBLY RH. Refer to «DISASSEMBLY - Step 25»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  28. REPLACE SEAT HEATER SWITCH. Refer to «REMOVAL»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  29. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»
  30. REPLACE SEAT HEATER SWITCH. Refer to «REMOVAL»(/lexus/rx/iii-2008-2012/remont/seats/#seat-service-information)
  31. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»

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

See also:
• REMOVAL

More articles — Climate Control Seat (Diagnostics)