Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Voltage is supplied to the audio steering wheel control momentary contact switches where the radio 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 it sends a serial data message that is received by the controlled component activating the feature.

Schematic Reference

Connector End View Reference

Entertainment Connector End Views

Electrical Information Reference

Caution: Refer to SIR Caution in the Preface section.

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 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 greater than 10.5 volts, test the voltage supply circuit for a short to voltage.

3. Test for 8.5-10.5 volts between the supply voltage circuit and both remote radio control signal circuits 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 is normal, replace the radio.

⇒	If greater than 10.5 volts, test the signal circuit for a 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 and the remote radio control signal circuit 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 the circuits test normal, test or replace the right switch.

⇒	If greater than 10.5 volts, repair the voltage supply circuit to the left switch for a short to voltage.

6. Test for 1-3 volts between the remote radio control signal circuit at the left switch harness connector and ground when pressing the down temperature 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 the circuits test normal, test or replace the left switch.

Caution: Refer to SIR Caution in the Preface section.

1. Ignition OFF, disconnect the harness connector at the suspect switch.
2. With all the switches in the open position, test the right switch for 2360-2400 ohms of resistance between the supply voltage circuit terminal and the supply voltage circuit terminal, that goes to the left switch.

⇒	If the resistance is not between 2360-2400 ohms of resistance, replace the right switch.

3. Test the left switch for infinite resistance between the remote radio control signal circuit and the supply voltage circuit terminals with all the switches in the open position

⇒	If less than infinite resistance, replace the left switch.

4. Test the resistance values between the supply voltage terminal and the signal terminal with the switch closed in each position and verify the readings are approximate to what the schematic reads.

⇒	If the values do not match, replace the appropriate switch.