Circuit/System Testing

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

1. Ignition OFF, disconnect the harness connector at the steering wheel control switches.
2. Ignition ON, Radio ON, test for 9.5-10.4 volts between the voltage circuit and ground at the right switch harness connector.
   • If less than 9.5 volts test the voltage circuit for short to ground or open/high resistance. If circuit test normal, replace the radio.
   • If greater than 10.4 volts, test the supply voltage circuit for short to voltage. If circuit test normal, replace the radio.
3. Ignition OFF, Install a 3-amp fused jumper wire in the right switch harness connector, between the voltage circuit and the voltage supply circuit to the left switch harness connector.
4. Ignition ON, Radio ON, test for 9.5-10.4 volts between the voltage circuit and ground at the left switch harness connector.
   • If less than 9.5 volts, repair the voltage supply circuit for short to ground or open/high resistance between the left and right switch harness connectors.
5. Ignition ON, Radio ON, connect a test lamp between the signal circuits to the radio and ground at the left and right switch connectors. Verify lamp does not illuminate.
   • If test lamp illuminates, test the signal circuits for short to voltage. If circuit test normal, replace the radio.
6. Ignition OFF, test for less than 1.0 ohm of resistance between the signal circuits to the radio and ground, at the left and right switch connectors.
   • If greater than 1.0 ohm, test the signal circuits for open/high resistance. If circuit test normal, replace the radio.
7. Ignition OFF, disconnect the harness connector at the radio and switches, 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 short to ground.
8. If circuit test normal, test or replace switch.