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Inspection Procedure 6: The indicator for the heated steering wheel switch does not come on. <Vehicles with heated steering wheel>
 
 

 
 
COMMENTS ON TROUBLE SYMPTOM
If the illumination light does not come on after the heated steering wheel switch is turned on, a component of the heated steering wheel, the power supply lines to the heated steering wheel or the indicator illumination circuit lines to the heated steering wheel switch may be defective.
 
 
 
TROUBLESHOOTING HINTS
  • Malfunction of heated steering wheel switch
  • Malfunction of clock spring
  • Defective steering wheel (incorporating heated steering wheel-ECU and heater element)
  • Defective harness wire(s) or connector(s)
    • Short or open circuit between the heated steering wheel relay and the heated steering wheel-ECU or loose connector contact
 
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the heated steering wheel switch.
Check the heated steering wheel switch (Refer to ).
Is the check result normal?
Go to Step 2.
Replace the heated steering wheel switch (Refer to ).
 
STEP 2. Check the clock spring.
Check whether the clock spring is in good condition (Refer to GROUP 52B - Air Bag Module and Clock Spring ).
Is the check result normal?
Go to Step 3.
Replace the clock spring (Refer to GROUP 52B - Air Bag Module and Clock Spring ).
 
STEP 3. Voltage measurement at the between C-319 clock spring connector (terminal No.2)
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3) Measure the voltage between the C-319 clock spring connector (terminal No.2) and body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 5.
Go to Step 4.
 
STEP 4. Check of short to power supply, short to ground, and open circuit in power supply line between heated steering wheel relay connector and C-319 clock spring connector (terminal No.2)
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).
Repair the connector(s) or wiring harness.
 
STEP 5. Retest the system
Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).
Replace the steering wheel assembly (Refer to ).