Climate Control Seat (Diagnostics): Overview Lexus IS II facelift

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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 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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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 U13 connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition U13-2 (IG) - U13-1 (GND) Engine switch on (IG) Blower switch ON (Vol: 1 to 3) 6.7 to 9.3 V NG --> See step 4 OK --> See step 20
4. CHECK HARNESS AND CONNECTOR Disconnect the U12 connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition U13-2 (IG) - U12-2 (CTB) Always Below 1 ohms U13-2 (IG) - Body ground Always 10 kohms or higher U13-1 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 21
5. CHECK HARNESS AND CONNECTOR Disconnect the U12 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard Voltage and Resistance Tester Connection Condition Specified Condition U12-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V U12-4 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
6. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY Reconnect the U12 connector. Check the input signal waveform. Connect the oscilloscope to terminal 3 and body ground with the climate control blower LH connector still connected. Check the signal waveform according to the condition(s) in the table below. Terminal No. U12-3 (SIGN) - Body ground Tool Setting 2 V/DIV., 500 μsec./DIV. Vehicle Condition Engine switch on (IG), seat hater switch ON NG --> See step 7 OK --> See step 22
7. CHECK HARNESS AND CONNECTOR Disconnect the U12 and J59 connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition U12-3 (SIGN) - J59-16 (LOUT) Always Below 1 ohms U12-3 (SIGN) - Body ground Always 10 kohms or higher 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»(ref-387380-S37394940652011022400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J45-8 (SVS5) - J45-10 (SVSG) Always 0.77 to 1.43 kohms J45-7 (BLLH) - J45-10 (SVSG) Blower switch OFF 0.77 to 1.43 kohms J45-7 (BLLH) - J45-10 (SVSG) Blower switch ON (Vol: 3) 110 to 270 ohms 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 J45-7(BLLH) - J59-2 (SW 5) Always Below 1 ohms J45-8 (SVS5) - J59-7 (S5-4) Always Below 1 ohms J45-10 (SVSG) - J59-10 (SG-4) Always Below 1 ohms J45-12 (E) - Body ground Always Below 1 ohms J45-7 (BLLH) - Body ground Always 10 kohms or higher J45-8 (SVS5) - Body ground Always 10 kohms or higher J45-10 (SVSG) - Body ground Always 10 kohms or higher 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 T13 connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition T13-2 (IG) - T13-1 (GND) Engine switch on (IG) Blower switch ON (Vol: 1 to 3) 6.7 to 9.3 V NG --> See step 12 OK --> See step 25
12. CHECK HARNESS AND CONNECTOR Disconnect the T12 connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T13-2 (IG) - T12-2 (CTB) Always Below 1 ohms T13-2 (IG) - Body ground Always 10 kohms or higher T13-1 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 26
13. CHECK HARNESS AND CONNECTOR Disconnect the T12 connector. Measure the voltage and resistance according to the value(s) in the table below. Standard Voltage and Resistance Tester Connection Condition Specified Condition T12-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V T12-4 (GND) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
14. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY Reconnect the T12 connector. Check the input signal waveform. Connect the oscilloscope to terminal 3 and body ground with the climate control blower RH connector still connected. Check the signal waveform according to the condition(s) in the table below. Terminal No. T12-3 (SIGN) - Body ground Tool Setting 2 V/DIV., 500 μsec./DIV. Vehicle Condition Engine switch on (IG), seat hater switch ON NG --> See step 15 OK --> See step 27
15. CHECK HARNESS AND CONNECTOR Disconnect the T12 and J59 connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition T12-3 (SIGN) - J59-8 (ROUT) Always Below 1 ohms T12-3 (SIGN) - Body ground Always 10 kohms or higher 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»(ref-387380-S37394940652011022400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J45-8 (SVS5) - J45-10 (SVSG) Always 0.77 to 1.43 kohms J45-9 (BLRH) - J45-10 (SVSG) Blower switch OFF 0.77 to 1.43 kohms J45-9 (BLRH) - J45-10 (SVSG) Blower switch ON (Vol: 3) 110 to 270 ohms 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 J45-9(BLRH) - J59-3 (SW 4) Always Below 1 ohms J45-8 (SVS5) - J59-7 (S5-4) Always Below 1 ohms J45-10 (SVSG) - J59-10 (SG-4) Always Below 1 ohms J45-12 (E) - Body ground Always Below 1 ohms J45-9 (BLRH) - Body ground Always 10 kohms or higher J45-8 (SVS5) - Body ground Always 10 kohms or higher J45-10 (SVSG) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 29
18. INSPECT SEAT HEATER SWITCH Remove the seat heater switch. Refer to «REMOVAL»(ref-387380-S37394940652011022400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J45-8 (SVS5) - J45-10 (SVSG) Always 0.77 to 1.43 kohms J45-9 (BLRH) - J45-10 (SVSG) Blower switch OFF 0.77 to 1.43 kohms J45-9 (BLRH) - J45-10 (SVSG) Blower switch ON (Vol: 3) 110 to 270 ohms J45-7 (BLLH) - J45-10 (SVSG) Blower switch OFF 0.77 to 1.43 kohms J45-7 (BLLH) - J45-10 (SVSG) Blower switch ON (Vol. 3) 110 to 270 ohms NG --> See step 30 OK: Go to next step
19. CHECK HARNESS AND CONNECTOR Disconnect the J59 connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition J45-8 (SVS5) - J59-7 (S5-4) Always Below 1 ohms J45-10 (SVSG) - J59-10 (SG-4) Always Below 1 ohms J45-8 (SVS5) - Body ground Always 10 kohms or higher J45-10 (SVSG) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 31
20. REPLACE SEAT BACK CLIMATE CONTROL BLOWER LH. Refer to «DISASSEMBLY - Step 33»(ref-387380-S10769864312011022400000)
21. REPLACE SEAT CLIMATE CONTROL BLOWER LH. Refer to «DISASSEMBLY - Step 32»(ref-387380-S10769864312011022400000)
22. REPLACE SEAT CLIMATE CONTROL BLOWER LH. Refer to «DISASSEMBLY - Step 33»(ref-387380-S10769864312011022400000)
23. REPLACE SEAT HEATER SWITCH. Refer to «REMOVAL»(ref-387380-S37394940652011022400000)
24. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-387355-S39716416222011022400000)
25. REPLACE SEAT BACK CLIMATE CONTROL BLOWER RH. Refer to «DISASSEMBLY - Step 31»(ref-387380-S10769864312011022400000)
26. REPLACE SEAT CLIMATE CONTROL BLOWER RH. Refer to «DISASSEMBLY - Step 32»(ref-387380-S10769864312011022400000)
27. REPLACE SEAT CLIMATE CONTROL BLOWER RH. Refer to «DISASSEMBLY - Step 32»(ref-387380-S10769864312011022400000)
28. REPLACE SEAT HEATER SWITCH. Refer to «REMOVAL»(ref-387380-S37394940652011022400000)
29. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-387355-S39716416222011022400000)
30. REPLACE SEAT HEATER SWITCH. Refer to «REMOVAL»(ref-387380-S37394940652011022400000)
31. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-387355-S39716416222011022400000)