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.
* Review with the schematic when testing switch resistance values.
* If a single switch function is inoperative, test the suspect switch. Refer to Component Testing.
* A poor connection at the right switch could cause both banks of switches to be inoperative.
Reference Information
Schematic Reference
Steering Wheel Secondary/Configurable Control Schematics (Steering Wheel Secondary/Configurable Control Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
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
Caution: Refer to SIR Caution (SIR Caution) .
Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing steering wheel controls.
1. Ignition OFF, disconnect the harness connector at the left and right steering wheel control switches.
2. Ignition ON, radio ON, test for 8.5-10.5 volts between the supply voltage circuit terminal 5 and ground at the right switch harness connector.
• If less than 8.5 volts test the voltage supply circuit for a short to ground or an open/ high resistance. If circuit test normal, replace the radio.
• If greater than 10.5 volts, test the voltage supply circuit for short to voltage. If circuit test normal, replace the radio.
3. Test for 8.5-10.5 volts from the supply voltage circuit terminal 5 and toggle to the signal circuits terminal 1 at the left and right switch harness connectors.
• If less than 8.5 volts, test the signal circuit for an open/ high resistance. If the circuit test normal, replace the radio.
• If greater than 10.5 volts, test the signal circuit for short to voltage. If the circuit test normal, replace the radio.
4. Ignition OFF, reconnect the right switch.
5. Ignition ON, radio ON, test for 8.5-10.5 volts between the supply voltage circuit terminal 4 and signal circuit terminal 1 at the left switch harness connector.
• If less than 8.5 volts test the voltage supply circuit to the left switch for a short to ground or an open/ high resistance. If circuit test normal, test or replace the right switch.
• If greater than 10.5 volts, repair the voltage supply circuit for a short to B+.
6. Test for 1-3 volts between the signal circuit terminal 1 and ground at the left switch harness connector when pressing the mute button.
• If less than 1 volt, test the signal circuit for a short to ground. If the circuit test is normal, test or replace the right switch.
7. If circuit test normal, test or replace the left switch.
Component Testing
Caution: Refer to SIR Caution (SIR Caution) .
1. Ignition OFF, disconnect the harness connector at the suspect switch.
2. Test the right switch for 2360-2400 ohms of resistance between both remote radio control supply voltage terminals 2 and 5 with the switch in the open position.
• If the resistance is not between 2360-2400 ohms of resistance, replace the right switch.
3. Test for infinite resistance between the supply voltage terminal 5 or terminal 4 and the signal terminal 1 with the switch in the open position.
• If less than infinite resistance, replace the switch.
4. Test resistance values between the supply voltage terminal 5 or terminal 4 and the signal terminal 1 with the switch closed in each position and verify readings are approximate to what the schematic reads.
• If the values do not match, 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