For 1990-2009 cars

Schematic Reference: Radio/Audio System Schematics

Important: 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.

1. Defective subwoofer -- Replace the subwoofer. Refer to Speaker Replacement Reference .
2. No audio output from amplifier -- Test for any AC voltage between the 2 pairs of audio signal circuits at the subwoofer 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 the affected speaker output circuits from the amplifier. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no shorts are located, replace the amplifier. Refer to Radio Speaker Amplifier Replacement .