Steering Wheel Controls Inoperative

Steering Wheel Controls Inoperative

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

Circuit/System Description
The radio supplies 10 volts 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 all the switches to be inoperative or malfunction.

Reference Information

Schematic Reference
Steering Wheel Schematics

Connector End View Reference
^ Entertainment Connector End Views
^ Steering Wheel and Column Connector End Views

Electrical Information Reference
^ Circuit Testing
^ Connector Repairs
^ Testing for Intermittent Conditions and Poor Connections
^ Wiring Repairs

Circuit/System Testing

Note: It is Recommend that Component Testing be performed before Circuit Testing when diagnosing steering wheel controls.

Caution: Refer to SIR Caution.

1. Ignition OFF, disconnect the harness connector at the left and right steering wheel control switches.
2. Ignition ON, Radio ON, test for 9.8 - 10.2 volts between the 10-volt reference circuit and ground at the right switch harness connector.
^ If less than 9.8 volts, test 10-volt reference circuit for short to ground or open/ high resistance. If circuit test normal, replace radio.
^ If greater than 10.2 volts, test the 10-volt reference circuit for short to voltage. If circuit test normal, replace radio.
3. Connect a test lamp between the steering wheel controls signal circuit and ground at the right switch harness connector. Verify test lamp does not illuminate.
^ If test lamp illuminates, test the signal circuit for a short to voltage. If circuit test normal, replace the radio.
4. Ignition OFF, test the jumper wire circuit for less than 1.0 ohm of resistance between the left and right switch harness connectors.
^ If greater than 1.0 ohm, repair jumper wire for an open/ high resistance.
5. Disconnect the harness connector at the radio.
6. Test for infinite resistance between the signal circuit and ground, at the radio harness connector.
^ If less than infinite resistance, test the signal circuit for a short to ground. If circuit test normal. Test or replace switch.
7. Test the steering wheel controls signal circuit for less than 1.0 ohm of resistance between the radio and switches.
^ If greater than 1.0 ohm, test the signal circuit for an open/high resistance.
8. If all circuits test normal, refer to component testing.

Component Testing

Caution: Refer to SIR Caution.

1. Ignition OFF, disconnect the harness connector at the suspect audio steering wheel control switch.
2. Test for infinite resistance between the supply voltage terminal and the signal terminal with the switch in the open position.
^ If less than infinite resistance, replace the switch.
3. Test resistance values between the supply voltage terminal and the signal terminal with the switch closed in each position and verify readings are approximate to what the schematic reads.
^ If values do not, replace the switch.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

^ Steering Wheel Control Switch Assembly Replacement
^ Control Module References for Radio replacement, setup, and programming.