Harness Related Noise
Noise induced into the speaker wires or any low level audio signal wire used as an interconnect between the various audio components.Some Causes
^ Broken, pinched, or shorted audio wires.
^ Screw through wire harness.
^ Faulty shield wires.
Solutions
^ Localize problem to left, right side, front, or back speaker location. Preferably done by using the fade and balance controls; if not, try reversing the speaker leads at the radio connector.
^ Check wiring for defects, breaks, pinches, or shorts.
^ Check wiring near known noisy components.