No Sound From One Ldspkr In Front Door But There Is From Others

No sound from one of the loudspeakers in the front doors but there is from the others

Fault symptoms
No sound from one of the loudspeakers.

Probable cause of fault
Break in a loudspeaker coil.
Break in a loudspeaker circuit or in the connection between the main unit and the amplifier.

Diagnostic help
Loudspeaker test: 4 channels.
Start the loudspeaker test by holding down the RADIO button when the main unit is switched on.

IMPORTANT
Check the balance and fader control settings.

Check wiring harness.
Jiggle the wiring harness at several points and in different directions to reveal intermittent breaks and short-circuits in the leads.
Observe the multimeter, test lamp or diagnostic instrument during the test.