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Steering Wheel Controls Inoperative (Preset/Vol)



Steering Wheel Controls Inoperative (Preset/Vol)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provide an overview of each diagnostic category.

Circuit/System Description

The CD Changer supplies voltage to the 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 CD Changer then identifies the switch selected to activate the feature, otherwise sends a serial data message that is received by the controlled component activating the feature.

Diagnostic Aids

* 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.
* A poor connection at the right switch could cause both banks of switches to be inoperative or malfunction.

Circuit/System Verification

Ignition ON, observe the scan tool Band status parameter while pressing and releasing the source switch. The reading should change bands.

Circuit/System Testing

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

Caution: Refer to Restraint System Service Precautions.

1. Ignition OFF, disconnect the C2 harness connector at the steering wheel control switch.
2. Ignition ON, test for 9.5-10.5 volts between the ignition circuit terminal 3 and ground.

• If less than the specified range, test the ignition circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the CD changer.
• If greater than the specified range, test the ignition circuit for a short to voltage. If the circuit tests normal, replace the CD changer

3. Test for 9.5-10.5 volts between the ignition circuit terminal and the signal circuit terminal 5.

• If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the CD changer.
• If greater than the specified range, test the signal circuit for a short to voltage. If circuit test normal, replace the CD changer.

4. Install a 3A fused jumper wire between the ignition terminal 3 and the signal circuit terminal 4.
5. Disconnect the C1 harness connector at the steering wheel controls.
6. Test for 9.5-10.5 volts between the signal circuit terminal 1 and ground.

• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the switch.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the switch.

7. Test for 9.5-10.5 volts between the signal circuit terminal 1 and the signal circuit terminal 2.

• If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the CD Changer.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the CD Changer.

8. Ignition OFF, disconnect the C1 harness connector at the CD Changer.
9. Test for infinite resistance between the signal circuit terminal 11 and ground.

• If less than the specified range, test the signal circuit for a short to ground.

10. If all circuits test normal, test or replace the steering wheel control switch.

Component Testing

Caution: Refer to Restraint System Service Precautions.

1. Ignition OFF, disconnect the C2 harness connector at the steering wheel control switch.
2. Test for less than 2,400 ohms between the ignition circuit terminal 3 and signal circuit terminal 4.

• If not the specified value, replace the steering wheel control switch.

3. Test for infinite resistance between the ignition circuit terminal 3 and the signal circuit terminal 5 with the switch in the open position.

• If not the specified value, replace the steering wheel control switch.

4. Test for less than 2,400 ohms between the ignition circuit terminal 3 and the signal circuit terminal 5 with the switch in the closed position.

• If not the specified value, replace the steering wheel control switch.

5. Disconnect the C1 harness connector at the steering wheel control switch.
6. Test for infinite resistance between the signal circuit terminal 1 and the signal circuit terminal 2.

• If not the specified value, replace the steering wheel control switch.

7. Test for less than 2,000 ohms between the signal circuit terminal 1 and the signal circuit terminal 2.

• If not the specified value, replace the steering wheel control switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Steering Wheel Control Switch Assembly Replacement
* Remote CD Changer Replacement. Verification Tests
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