The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - What would cause the 12gauge wire at the Junction box to ground?

mr.precision · 09-28-2019, 10:15 AM

Had a look yesterday.
First thing I noticed is the battery has REVERSED POLARITY. Yes that is right. With everything disconnected, my meter was showing -12.28 volts. Gotta say in my many years of fooling with vintage cars and trucks, I have never seen this before.
Alternator has no internal ground, so it may be OK.

Only explanation I can think of is that the battery was disconnected with a battery tender hooked up. Perhaps the battery tender reversed itself, if that is possible.

I brought the battery, alternator, and regulator back to my place. One thing I did notice is that the harness is fried all the way to the alternator, which I hadn't seen before. So I am going to need to fabricate a harness before putting a new battery back in and testing everything.

09-28-2019, 10:15 AM	#7
mr.precision Registered User Join Date: Feb 2018 Location: Fountain Hills, AZ Posts: 161	Re: What would cause the 12gauge wire at the Junction box to ground? Had a look yesterday. First thing I noticed is the battery has REVERSED POLARITY. Yes that is right. With everything disconnected, my meter was showing -12.28 volts. Gotta say in my many years of fooling with vintage cars and trucks, I have never seen this before. Alternator has no internal ground, so it may be OK. Only explanation I can think of is that the battery was disconnected with a battery tender hooked up. Perhaps the battery tender reversed itself, if that is possible. I brought the battery, alternator, and regulator back to my place. One thing I did notice is that the harness is fried all the way to the alternator, which I hadn't seen before. So I am going to need to fabricate a harness before putting a new battery back in and testing everything.