Radio Works, But Audio Switch Does Not Function; Weak Or Noisy Reception; Avc (Auto Volume Control) Does Not Work At All; Radio Works, But Audio Display Does Not Appear - Honda GL1800 Service Manual

Radio works, but audio switch does not function

1. Audio Switch Inspection
Check the audio switch that does not function (page 22-9).
Does the switch test OK?
NO – Faulty audio switch.
YES – GO TO STEP 2.
2. Audio Switch Line Inspection
Check the related audio switch lines (page 22-7).
Is continuity correct?
NO – Open or short circuit in wire between the audio switch and audio unit.
YES – • Loose or poor related connection.
• Faulty audio unit.

Weak or noisy reception

1. Antenna Connection Inspection
• Use of the ambience (AMB) circuit may cause weak FM signals.
• As FM stereo reception becomes weaker, special circuits in the radio gradually blend the sound
toward monaural to maintain some sound quality, even though the "STEREO" indication remains
on.
Remove the seat (page 2-5).
Check for loose or poor antenna connection.
Are all antenna connections good?
NO – Correct the faulty part.
YES – GO TO STEP 2.
2. Antenna Base Inspection
Check the antenna base (page 22-11).
Is continuity correct?
NO – Faulty antenna base.
YES – • Loose or poor related connection.
• Faulty condenser in the alternator or cooling fan motor.
• Faulty audio unit.

AVC (Auto Volume Control) does not work at all

1. Speedometer Inspection
Check that the speedometer operates properly.
Is the speedometer operating properly?
NO – Check the speedometer (page 20-20).
YES – GO TO STEP 2.
2. Speed Pulse Signal Line Inspection
Check the speed pulse signal line (page 22-8).
Is the voltage within the specified voltage?
NO – Open or short circuit in White/black wire between the combination meter and audio unit.
YES – • Loose or poor related connection.
• Faulty audio unit.

Radio works, but audio display does not appear

1. Audio Display Signal Line Inspection
Check the audio display signal lines (page 22-7).
Is continuity correct?
NO – Open or short circuit in the wire between the combination meter and audio unit.
YES – • Loose or poor related connection.
• Faulty audio unit.
AUDIO SYSTEM
22-5