Check both positive cable and negative (ground) at the battery post. If okay begin the tedious
process of finding a loose ground wire.

This happened to me riding the 07 Street Bob from Leakey to Houston one weekend.
Checked the battery and the ground cable had loosened from the post. Stainless lock
washer with red battery grease and about 10K miles no issues.

The next weekend the positive cable backed out of the battery post. So another
stainless lock washer and dose of battery grease to the rescue.

FWIW-Helped a stranded rider in Smithville with the same issue on a Street Bob.

Good Luck,
Woodreaux

 

I've had the positive connection come loose before, but it was connected enough so you would turn the key on get lights hit the starter and everything went dead.

Also you could get water in the kill switch, happened to a guy I was riding with on his SE Wide Glide. We were riding in rain some heavy that day and his bike just quit when we came to a stop sign, everything went dead. He kept playing withthe switchand finally got it to work again.

 

definitely give the battery cables a good tightening... pretty much same thing happened to me. except weather was better!