Diagnosing AM Band Alternator Wine and Ignition Noise

C. Diagnosing AM Band Alternator Whine:

Alternator noise is heard as a smooth, high pitched "whine" (as opposed to a low pitched, rough "tick" of ignition noise). The pitch of the whine will vary with engine RPM. The volume of the whine may also vary with changes in the electrical load (eg. headlamps and heated backlight).

D. Diagnosing AM Band Ignition Noise:

Ignition noise is heard as a sharp or rough "tick" (as opposed to the higher pitched smooth whine of alternator noise). The frequency of the "tick" varies with RPM.