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On Day two of being a first time M37 owner, I took a 10 mile drive to show my Brother my proud purchase. Parked the truck and noticed a smell of something being real hot. Popped the hood and after investigating narrowed it down to the regulator. It was Very got to the touch, 15 minutes of BS later, the truck wouldn't turn over. We found the positive battery cable to also be very warn, and one battery to be reading 5.4 volts negative polarity. I know I need to replace the one battery, but what is up with the hot regulator? Will a new battery suffer the same fate for some reason?

Thanks....
Roger... a newbie searching for help.

If the truck has been modified with a midpoint tap for 12-Volt stuff, get rid of it immediately.

It will cause this type of failure, but may not be the only problem.

A hot regulator points to a stuck cutout contact. Properly wired trucks have the regulator disconnected any time the ignition switch is off thru a second set of contacts in it. This was done to act as a failsafe from regulator failure.

If someone put in a key switch, that regulator connection is probably hot at all times.

PoW

No 12 volt cut in that I can see. The issue wasn't the regulator heating up while parked..ie, the ignition switch sending it power when it shouldn't. The hot temperature of the regulator occurred while driving. What would cause that?