Heated Steering Wheel Malfunction

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performanc
Ignition	1	1	—	—
Switch Signal	2	1	—	—
Switch and LED Ground	—	1	—	—
Temperature Sensor Signal	3	3	3	—
Temperature Sensor Ground	—	3	—	—
Heater Element Control	3	3	2	—
Heater Element Ground	—	3	—	—
Module Ground	—	1	—	—
1. Heated Steering Wheel System Inoperative 2. Heated Steering Wheel Always ON 3. Heated Steering Wheel Inoperative

Circuit/System Description The heated steering wheel control module controls the heated steering wheel and the heated steering wheel ON indicator based on an input from the heated steering wheel switch. When the heated steering wheel switch is pressed, the switch signal circuit is pulled to ground. This indicates to the heating steering wheel control module that steering wheel heat is requested. When the request is seen, the heated steering wheel control module supplies voltage to the indicator lamp and supplies voltage to the heating elements, which are internal to the steering wheel. Diagnostic Aids Before replacing the steering wheel for complaints of not getting hot enough, a reliable infrared temperature gun should be used to measure the temperature at various points around the rim. The steering wheel’s normal operating temperature is 32°C (89.6°F) and takes approximately 10 min to reach that temperature. It may take up to 20 min for the normal operating temperature to stabilize within the steering wheel rim. There may be spike in temperature during the first 3–4 min before it stabilizes at normal operating temperature. The steering wheel will take longer to heat up if the vehicle temperature is below -21°C (-5.8°F). The steering wheel heater will not operate when the steering wheel temperature is above 32°C (89.6°F).

Heated Steering Wheel Malfunction — figure 1

The infrared measurements are made at the rim (1) at the 3 and 9 o’clock positions of the steering wheel. Reference Information Schematic Reference Steering Wheel Schematics Connector End View Reference Master Electrical Component List Description and Operation Steering Wheel and Column Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Circuit/System Verification Using an Infrared Temperature Gun

1. Engine running, all accessories OFF.
2. Verify the Heated Steering Wheel Switch – S70L Cruise Control Switch is OFF and the steering wheel heater indicator is not be illuminated. ⇒ If the heater indicator is illuminated Refer to Heated Steering Wheel Indicator Malfunction ⇓ If the heater indicator is not illuminated

Note

The Infrared Temperature Gun should be within 50.8mm (2 in) and parallel to the steering wheel rim when taking temperature readings.

3. Measure the temperature readings at the 3 and 9 o’clock positions on the steering wheel rim.
4. Verify that the steering wheel temperature is 25°C (77°F) or below. ⇒ If the steering wheel temperature is greater than 25°C (77°F) Allow the steering wheel to cool before proceeding to next step. ⇓ If the steering wheel temperature is 25°C (77°F) or below
5. Press and release the Heated Steering Wheel Switch – S70L Cruise Control Switch. The steering wheel heater indicator should illuminate. Allow the steering wheel to heat for a minimum of 10 min so that the temperature stabilizes. ⇒ If the heater indicator does not illuminate Refer to Heated Steering Wheel Indicator Malfunction ⇓ If the heater indicator illuminates
6. Measure the temperature readings at the 3 and 9 o’clock positions on the steering wheel rim.
7. Verify that the steering wheel temperature is greater than 28°C (82.4°F) within 20 min. ⇒ If after 20 minutes the measured temperature is less than 28°C (82.4°F) Refer to Circuit System Testing. ⇓ If after 20 minutes the measured temperature is 28°C (82.4°F) or greater
8. All OK. Circuit/System Testing
9. Ignition ON.
10. Verify that no communication DTCs are set. ⇒ If any DTCs are set Refer to Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If no DTCs are set
11. Ignition OFF, disconnect the X1 harness connector at the K32 Heated Steering Wheel Module
12. Test for less than 10 Ω between the ground circuits listed below and ground: Terminal 4 Terminal 5 ⇒ If 10 Ω or greater 4.1. Ignition OFF. 4.2. Test for less than 2 Ω in the ground circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, repair the open/high resistance in the ground connection. ⇓ If less than 10 Ω
13. Ignition ON.
14. Verify a test lamp illuminates between the ignition voltage circuit terminal 3 and ground. ⇒ If the test lamp does not illuminate and the circuit fuse is good 6.1. Ignition OFF, remove the test lamp. 6.2. Test for less than 2 Ω in the ignition circuit end to end. ⇒ If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse. Refer to Power Mode Mismatch. 6.3. Verify the in-line fuse is OK and there is voltage at the fuse. ⇒ If the in-line fuse is blown, replace the K32 Heated Steering Wheel Module. ⇒ If the in-line fuse is OK, repair the open/high resistance in the circuit. ⇒ If the test lamp does not illuminate and the circuit fuse is open 6.1. Ignition OFF. 6.2. Test for infinite resistance between the ignition voltage circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇒ If infinite resistance, replace the K32 Heated Steering Wheel Module. ⇓ If the test lamp illuminates
15. Ignition OFF, connect the X1 harness connector at the K32 Heated Steering Wheel Module. Disconnect the harness connector at the S70L Cruise Control Switch.
16. Test for less than 10 Ω between the ground circuit terminal 6 and ground. ⇒ If 10 Ω or greater 8.1. Ignition OFF. 8.2. Test for less than 2 Ω in the ground circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, repair the open/high resistance in the ground connection. ⇓ If less than 10 Ω
17. Ignition ON.
18. Test for B+ between the signal circuit terminal 8 and ground. ⇒ If less than B+ 10.1. Ignition OFF, disconnect the X1 harness connector at the K32 Heated Steering Wheel Module. 10.2. Test for infinite resistance between the control circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 10.3. Test for less than 2 Ω in the control circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K32 Heated Steering Wheel Module. ⇓ If B+
19. Ignition OFF, disconnect the X1 harness connector at the K32 Heated Steering Wheel Control Module.
20. Ignition ON.
21. Test for less than 1 V between the signal circuit terminal 1 and ground. ⇒ If greater than 1 V Repair the short to voltage on the circuit. ⇓ If less than 1 V
22. Ignition OFF, connect the X1 harness connector at the K32 Heated Steering Wheel Control Module.
23. Test for infinite resistance between terminal 8 and terminal 6 at the S70L Cruise Control Switch with the steering wheel heater switch released ⇒ If less than infinite resistance Replace the S70L Cruise Control Switch. ⇓ If infinite resistance
24. Test for less than 40 Ω between terminal 8 and terminal 6 at the S70L Cruise Control Switch with the steering wheel heater switch pressed. ⇒ If 40 Ω or greater Replace the S70L Cruise Control Switch ⇓ If less than 40 Ω
25. Connect the harness connector at the S70L Cruise Control Switch. Disconnect the X2 harness connector at the E15 Steering Wheel Heater.
26. Test for less than 10 Ω between the ground circuits listed below and ground. Terminal 2 Terminal 3 ⇒ If 10 Ω or greater Repair the open/high resistance in the circuit. ⇓ If less than 10 Ω
27. Test for 1.5–3.0 Ω between the signal terminal 1 and the ground terminal 2 at the E15  Steering Wheel Heater. ⇒ If not within the specified range Replace the E15 Steering Wheel Heater. ⇓ If within the specified range
28. Test for 9–11k Ω between the control circuit terminal 4 and the ground terminal 3 on the E15  Steering Wheel Heater. ⇒ If not within the specified range Replace the E15 Steering Wheel Heater. ⇓ If within the specified range
29. Replace the K32 Heated Steering Wheel Module. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Steering Wheel Replacement Control Module References for control module replacement, programming and setup.