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**VetteVet** · 08-28-2021, 12:43 PM

The brown wire comes from the key switch and runs through a 10 ohm light (resistance) on the light dashes and also through a resistance wire on the gauge dashes. This resistance wire is there to protect the charging circuit to the VR in case the light goes out (blows).
I would run a jumper from a 12 volt hot source in series with a 10 ohm resistance to the brown wire connection on the VR and see if the buzzing stops. I have an external wire like this on my truck and it works fine. Temporary for testing of course for an SI alternator.

08-28-2021, 12:43 PM	#11
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,703	Re: buzzing external voltage regulator 72 K5 blazer The brown wire comes from the key switch and runs through a 10 ohm light (resistance) on the light dashes and also through a resistance wire on the gauge dashes. This resistance wire is there to protect the charging circuit to the VR in case the light goes out (blows). I would run a jumper from a 12 volt hot source in series with a 10 ohm resistance to the brown wire connection on the VR and see if the buzzing stops. I have an external wire like this on my truck and it works fine. Temporary for testing of course for an SI alternator. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.