Criss-crossing jumper cables: What would happen?

[48Willys]

@GreasyJack

Do you have a cite on that? I’m almost positive (:)) they were negative ground from the start and googling the only references to them being positive ground seem to be from people who think 6 volt and positive ground always go together.

And yeah, once they got to the fusebox red= unswitched hot and black = switched hot but usually the positive battery cable was just a big beefy black wire. Sometimes the smaller wire that actually went to the fusebox was red, but not always.

I have owned over 25 VWs built from 1955 to 1966, all six volt, and NONE were positive ground. I have just checked two of my VW maintenance manuals. Both manuals state that the electrical system is six volt negative ground. I believe they were all negative ground.

Like GreasyJack said “Early VW’s were 6 volt, but I don’t think they were ever positive ground. That was almost entirely a British thing.”

Note the almost. Some early US built trucks & tractors were positive ground. For example the 1945 ish Caterpillar D-2 was six volt positive ground. Safety tip: When jump starting an early D-2 with a six volt VW, do not let the door to the VW touch the tracks on the D-2. AMHIK!