Schematic Reference: 
Radio/Audio System Schematics 
   
All Speakers Inoperative
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.
With RPO U62
- Speaker output shorted - Test all speaker outputs for a short. Refer 
to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- Defective Radio - Replace Radio. Refer to 
Radio Replacement 
.
 
With RPO UQ3
- Battery positive voltage circuit to the amplifier open. Test the battery
 positive voltage circuit to the amplifier for an open. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- Ground circuit to the amplifier open. Test the ground circuit to the 
amplifier for an open. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- Antenna enable signal circuit to the amplifier open or shorted to ground.
 Test the antenna enable signal circuit for an open or short to ground. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- No audio output from the amplifier. Replace the amplifier. Refer to 
Radio Speaker Amplifier Replacement 
.
 
Important: The following procedure assumes all speakers are operative for all modes of
 operation except digital radio.
With RPO U2K or U2L
- Remote radio audio signal circuit shorted. Test the remote radio audio
 signal circuits for a short. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- No audio output from the digital radio receiver. Replace the digital radio
 receiver. Refer to 
Digital Radio Receiver Replacement 
 and 
Digital Radio Receiver Setup 
.
 
- No digital radio audio output from the radio. Replace the radio. Refer
 to 
Radio Replacement 
.
 
One Speaker Inoperative
Important: The following information lists the most probable cause of the concern to  the
least probable cause. If the list leads to the replacement of a component, always
 inspect for a poor connection before proceeding with replacement. Refer to 
Testing for Intermittent Conditions and Poor Connections 
 and 
Connector Repairs 
 in Wiring Systems.
With RPO U62
- Speaker output open. Test the appropriate speaker output circuits for
 an open. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- No audio output from the radio. Test for any AC voltage between the  appropriate
speaker output circuits at the speaker harness connector, disconnected  with the radio
volume adjusted to 50 percent. If AC voltage is present, replace  the speaker. Refer
to 
Speaker Replacement Reference 
.   If no AC
voltage is present, replace the radio. Refer to 
Radio Replacement 
.
 
With RPO UQ3
- Speaker output circuit from amplifier open. Test the appropriate speaker
 output circuits for an open. Refer to 
Circuit Testing 
  and 
Wiring Repairs 
 in Wiring
Systems.
 
- No audio output from the amplifier. Test for any AC voltage between  
the appropriate speaker output circuits at the speaker harness connector, disconnected
 with the radio volume adjusted to 50 percent. If AC voltage is present, replace 
the speaker. Refer to 
Speaker Replacement Reference 
.
  If no AC voltage is present, replace the amplifier. Refer to 
Radio Speaker Amplifier Replacement 
.
 
Speakers - One Channel Inoperative
Important: The following information lists the most probable cause of the concern to  the
least probable cause. If the list leads to the replacement of a component, always
 inspect for a poor connection before proceeding with replacement. Refer to 
Testing for Intermittent Conditions and Poor Connections 
 and 
Connector Repairs 
 in Wiring Systems.
With RPO UQ3
- Speaker output circuit from amplifier shorted. Test the appropriate  
speaker output circuits for a short. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- No audio output from the amplifier. Test for any AC voltage between  
 the appropriate speaker output circuits at the speaker harness connector, disconnected
 with the radio volume adjusted to 50 percent. If AC voltage is present, replace 
the speaker. Refer to 
Speaker Replacement Reference 
.
 If no AC voltage is present, replace the amplifier. Refer to 
Radio Speaker Amplifier Replacement 
.
 
Important: The following procedure assumes all speakers are operative for all modes of
 operation except digital radio.
With RPO U2K or U2L
- Remote radio audio signal circuit open. Test the appropriate remote radio
 audio signal circuit for an open. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- No audio output from the digital radio receiver. Replace the digital radio
 receiver. Refer to 
Digital Radio Receiver Replacement 
 and 
Digital Radio Receiver Setup 
.
 
- No digital radio audio output from the radio. Replace the radio. Refer
 to 
Radio Replacement 
.
 
Speakers - Reduced Volume / Audio Distortion
Important: The following information lists the most probable cause of the concern to  the
least probable cause. If the list leads to the replacement of a component, always
 inspect for a poor connection before proceeding with replacement. Refer to 
Testing for Intermittent Conditions and Poor Connections 
 and 
Connector Repairs 
 in Wiring Systems.
With RPO U62
- Speaker output circuit high resistance. Test the appropriate speaker 
  output circuits for high resistance. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring
 Systems.
 
- Defective speaker - Replace the appropriate speaker. Refer to 
Speaker Replacement Reference 
.
 
With RPO UQ3
- Speaker output circuit high resistance. Test the appropriate speaker 
output circuits from the audio amplifier for high resistance. Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- Defective speaker - Replace the appropriate speaker. Refer to 
Speaker Replacement Reference 
.
 
Important: The following procedure assumes all speakers are operative for all modes of
 operation except digital radio.
With RPO U2K or U2L
- Audio common circuit open. Test the audio common circuit for an open.
 Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- No audio output from the digital radio receiver. Replace the digital radio
 receiver. Refer to 
Digital Radio Receiver Replacement 
 and 
Digital Radio Receiver Setup 
.
 
- No digital radio audio output from the radio. Replace the radio. Refer
 to 
Radio Replacement 
.