Steering Wheel Does Not Heat Up When Heated Steering Wheel Switch Is Pressed

STEERING COLUMN: HEATED STEERING WHEEL SYSTEM: Steering Wheel does not Heat Up When Heated Steering Wheel Switch is Pressed
- Steering Wheel does not Heat Up When Heated Steering Wheel Switch is Pressed

DESCRIPTION

Description and Operation.

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT
* 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.

PROCEDURE

1. INSPECT STEERING WHEEL ASSEMBLY (THERMISTOR-HEATER-THERMOSTAT)

(a) Disconnect the B steering wheel controller connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Text in Illustration

NG -- REPLACE STEERING WHEEL ASSEMBLY Removal
OK -- Continue to next step.

2. INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY

(a) 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.

(b) Disconnect the H45 and z14 spiral with sensor cable sub-assembly connectors.

(c) Disconnect the heated steering wheel controller connector.

(d) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Text in Illustration

NG -- REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY Removal
OK -- Continue to next step.

3. CHECK STEERING HEATER SWITCH

(a) Disconnect the H42 steering heater switch connector.

(b) Measure the voltage according to the value(s) in the table below.

HINT
As the circuit has a diode, perform the measurement in diode test mode, and do not mistake the polarity.

Standard Voltage:

Text in Illustration

NG -- REPLACE STEERING HEATER SWITCH Removal
OK -- Continue to next step.

4. CHECK STRG HTR RELAY (STEERING HEATER RELAY)

(a) Remove the STRG HTR relay (steering heater relay).

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Text in Illustration

NG -- REPLACE STRG HTR RELAY (STEERING HEATER RELAY)
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH - SPIRAL W/ SENSOR CABLE SUB-ASSEMBLY)

(a) Disconnect the H42 steering heater switch connector.

(b) Disconnect the H45 spiral with sensor cable sub-assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (STRG HTR RELAY - SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY)

(a) Remove the STRG HTR relay (steering heater relay) from the relay block No. 3.

(b) Disconnect the H45 spiral with sensor cable sub-assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH POWER SOURCE)

(a) Disconnect the H42 steering heater switch connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (STRG HTR RELAY (STEERING HEATER RELAY) POWER SOURCE)

(a) Remove the STRG HTR relay (steering heater relay) from the relay block No. 3.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY BODY GROUND)

(a) Disconnect the H45 spiral with sensor cable sub-assembly connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE STEERING WHEEL HEATER CONTROL ASSEMBLY Removal