DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT STEERING WHEEL ASSEMBLY (THERMISTOR·HEATER·THERMOSTAT)
INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY
CHECK STEERING HEATER SWITCH
CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH - SPIRAL W/ SENSOR CABLE SUB-ASSEMBLY)
CHECK HARNESS AND CONNECTOR (IG CIRCUIT)
CHECK HARNESS AND CONNECTOR (IG CIRCUIT)
CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY BODY GROUND)
HEATED STEERING WHEEL SYSTEM - Steering Wheel does not Heat Up When Heated Steering Wheel Switch is Pressed
DESCRIPTION
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WIRING DIAGRAM
INSPECTION PROCEDURE
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
The steering heater unit is built into the steering wheel assembly which cannot be disassembled. Therefore, when the steering heater unit has a malfunction, replace the steering wheel assembly.
| 1.INSPECT STEERING WHEEL ASSEMBLY (THERMISTOR·HEATER·THERMOSTAT) |
Disconnect the B steering wheel controller connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| B-1 (TH1) - B-2 (TH2) | 10 to 30°C (50 to 86°F) | 8.132 to 18.43 kΩ |
| B-4 (SH1) - B-3 (SH2) | 20°C (68°F) | 1.89 to 2.25 Ω |
Text in Illustration| *a | Front view of wire harness connector
(to Steering Wheel Control Assembly) |
| | REPLACE STEERING WHEEL ASSEMBLY ()
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| 2.INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY |
Check the connectors and cables of the spiral with sensor cable sub-assembly.
- OK:
- There are no defects such as scratches, cracks, dents or damage on the connectors or cables.
Disconnect the E107 and z63 spiral with sensor cable sub-assembly connectors.
Disconnect the heated steering wheel controller connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| z63-1 (CCU) - E107-1 (BTM) | Always | Below 1 Ω |
| z63-2 (CCV) - E107-3 (ETM) | Always | Below 1 Ω |
| z63-3 (CCX) - E107-2 (EHT) | Always | Below 1 Ω |
| z63-4 (CCW) - E107-4 (BHT) | Always | Below 1 Ω |
Text in Illustration| *a | Component without harness connected
(Spiral with Sensor Cable Sub-assembly) | - | - |
| | REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY ()
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| 3.CHECK STEERING HEATER SWITCH |
Disconnect the G14 steering heater switch connector.
Measure the voltage according to the value(s) in the table below.
- As the circuit has a diode, perform the measurement in diode test mode, and do not mistake the polarity.
- Standard Voltage:
Tester Connection
(Positive (+) tester probe - Negative (-) tester probe) | Condition | Specified Condition |
| G14-3 (IG) - G14-7 (+) |
Always | Below 1.25 V |
| G14-6 (IN) - G14-7 (+) |
Steering heater switch is pushed | Below 1.25 V |
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| G14-3 (IG) - G14-6 (IN) | Steering heater switch is pushed | Below 1 Ω |
| G14-3 (IG) - G14-6 (IN) | Steering heater switch is not pushed | 10 kΩ or higher |
Text in Illustration| *a | Component without harness connected
(Steering Heater Switch) |
| | REPLACE STEERING HEATER SWITCH ()
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| 4.CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH - SPIRAL W/ SENSOR CABLE SUB-ASSEMBLY) |
Disconnect the G14 steering heater switch connector.
Disconnect the E107 spiral with sensor cable sub-assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| G14-7 (+) - E107-1 (BTM) | Always | Below 1 Ω |
| G14-6 (IN) - E107-3 (ETM) | Always | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 5.CHECK HARNESS AND CONNECTOR (IG CIRCUIT) |
Disconnect the G14 steering heater switch connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| G14-3 (IG) - Body ground | Ignition switch ON | 11 to 14 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 6.CHECK HARNESS AND CONNECTOR (IG CIRCUIT) |
Disconnect the E107 spiral with sensor cable subassembly connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| E107-4 (BHT) - Body ground | Ignition switch ON | 11 to 14 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 7.CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY BODY GROUND) |
Disconnect the E107 spiral with sensor cable sub-assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| E107-2 (EHT) - Body ground | Always | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| OK | |
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| REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY ()
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