Steering Wheel Controls Inoperative
Steering Wheel Controls Inoperative
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Circuit/System Description
The radio supplies voltage to the audio steering wheel control momentary contact switches, and monitors the return signal. Each switch is associated to a set resistance value, when pressed a specific voltage drop occurs through a series of resistors unique to that switch. The radio then identifies the selection to activate the feature, otherwise sends a serial data message that is received by the controlled component activating the feature.
Diagnostic Aids
* This diagnostic is for the audio steering wheel controls.
* Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.
* If a single switch function is inoperative, test the suspect switch. Refer to component testing.
Reference Information
Schematic Reference
Steering Wheel Secondary/Configurable Control Schematics (Steering Wheel Secondary/Configurable Control Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Steering Wheel Controls Description and Operation (Steering Wheel Controls Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Circuit/System Testing
Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing steering wheel controls.
Caution: Refer to SIR Caution (SIR Caution).
1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Ignition ON, Radio ON, test for 8.5-10.5 volts between the supply voltage circuit terminal 3 and ground.
• If less than the specified range test the supply voltage circuit for a short to ground or an open/high resistance. If circuit test normal, replace the radio.
• If greater than the specified range, test the supply voltage circuit for short to voltage. If circuit test normal, replace the radio.
3. Test for 8.5-10.5 volts between the supply voltage circuit terminal 3 and the signal circuit terminal 4.
• If less than the specified range, test the signal circuit for an open/high resistance. If circuit test is normal, replace the radio.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit test is normal, replace the radio.
4. Ignition OFF, disconnect the X1 harness connector at the radio.
5. Test for infinite resistance between the signal circuit terminal A7 and ground.
• If not the specified value, test the signal circuit for a short to ground.
6. If all circuits test normal, test or replace the switch.
Component Testing
Caution: Refer to SIR Caution (SIR Caution).
1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
2. Test for infinite resistance between the signal circuit terminal 4 and voltage circuit terminal 3 with the switch in the open position.
• If not the specified value, replace the switch.
3. Test for less than 6,800 ohms of resistance between the signal circuit and the voltage circuit with the switch in the closed position.
• If greater than the specified range, replace the switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Steering Wheel Control Switch Assembly Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for radio replacement, setup, and programming