For 1990-2009 cars

Schematic Reference: Radio/Audio System Schematics

Important: The following information lists the most probable cause of the concern to the least probable cause, followed by the appropriate test for that condition. If the list leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

#### Without RPO WBM

No audio output from the radio.

Test for any AC voltage between the left front audio signal circuits at the left front speaker connector with the radio volume adjusted to 50 percent. If no AC voltage is present, check for shorts to battery positive or shorts to ground on any speaker output circuit from the radio. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no shorts are located, replace the radio. Refer to Radio Replacement .

#### With RPO WBM

1. Battery positive voltage to the amplifier open.

Test the battery positive circuit to the amplifier for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

2. Ground to the amplifier open.

Test the ground circuit to the amplifier for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

3. No low level audio output from the radio.

Test for any AC voltage between the left front low level audio signal circuits at the amplifier connector with the radio volume adjusted to 50 percent. If no AC voltage is present, check for shorts to battery positive or shorts to ground on any speaker output circuit from the radio. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no shorts are located, replace the radio. Refer to Radio Replacement .

4. No radio on signal to the amplifier

Test the radio on signal circuit to the amplifier for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

5. Defective amplifier

Replace the amplifier. Refer to Radio Speaker Amplifier Replacement .