Lexus NX: Seat Heater Switch Circuit
DESCRIPTION
When the refreshing seat switch is operated, the air conditioning amplifier assembly receives the signal via the LIN communication line, and operates the seat heater for the corresponding rear seat.
WIRING DIAGRAM
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CAUTION / NOTICE / HINT
NOTICE:
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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.
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.
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If the auxiliary battery voltage is low, the seat heater system may not operate. Refer to Data List for the power steering system.
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for Manual Tilt and Manual Telescopic Steering Column:
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for Power Tilt and Power Telescopic Steering Column:
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for Manual Tilt and Manual Telescopic Steering Column:
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When the auxiliary battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.
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PROCEDURE
| 1. | CHECK HARNESS AND CONNECTOR (REFRESHING SEAT SWITCH - BATTERY AND BODY GROUND) |
| (a) Disconnect the refreshing seat switch connector. |
|
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I158-1 (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 |
|---|---|---|
| I158-5 (IG) - Body ground | Power switch off | Below 1 V |
| I158-5 (IG) - Body ground | Power switch on (IG) | 11 to 14 V |
| NG | .gif) | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
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| 2. | CHECK HARNESS AND CONNECTOR (REFRESHING SEAT SWITCH - AIR CONDITIONING AMPLIFIER ASSEMBLY) |
(a) Disconnect the I158 refreshing seat switch connector.
(b) Disconnect the I54 air conditioning amplifier assembly connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I158-3 (RLIN) - I54-16 (RLIN) | Always | Below 1 Ω |
| I158-3 (RLIN) or I54-16 (RLIN) - Body ground | Always | 10 k Ω or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (OUTPUT SIGNAL) |
| (a) Using an oscilloscope, check the waveform.
OK: The waveform displays properly. |
|
| NG | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
|
| 4. | CHECK REFRESHING SEAT SWITCH (OUTPUT SIGNAL) |
| (a) Using an oscilloscope, check the waveform.
OK: The waveform displays properly. |
|
| NG | | REPLACE REFRESHING SEAT SWITCH |
|
| 5. | INSPECT REFRESHING SEAT SWITCH |
(a) Remove the refreshing seat switch.
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(b) Inspect the refreshing seat switch.
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| OK | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
| NG | | REPLACE REFRESHING SEAT SWITCH |
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