This is a really long shot, but something pretty easy to check and correct if necessary.

Double check the integrity of the ground connection between battery and chassis. You said you had ground running from the battery to both engine and chassis... if the ground connection at the chassis is compromised (loose fastener, corrosion or paint under the connecter, etc.) this can set you up for all kinds of weird problems like the radio only works when the windshield wipers are on, or the horn beeps when you turn on the turn signals. It might also cause an enhancement of alternator whine if all your chassis ground reqirements were being met by having to run "backwards" through the alternator ground circuit.

tanstaafl.



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