Dead short?

There is a white connector under the column that attaches the switch harness to the dash harness. I suspect you'll find it melted to the point it created a short circuit.
Other circuits like the shift indicator lamp and switch light time delay really shouldn't have been placed in that same connector but they were. Those are the circuits that relate the little ground jumper at column mounting.
FYI The horn circuit uses that ground jumper also but it's in the other connector to signal switch.