Well, it turns out the wire was loose. Specifically, a C-connector I bent to "plug" into the OEM harness (read: jammed in).

I finally opened it up and saw the loose wire took a bit of effort to fix since the wire unwounded itself into a slightly hard to reach spot.

Need o get some e-tape to wrap it for now.

 

I clipped one side of the connector you're talking about to get it to fit, a bit cleaner maybe, then did a tape wrap. You've just given me a heads up on watching it though.

I was thinking at the time of using shrink tube to finish it off. That was then...

 

Shrink tubing would be good, but I feel even that is too permanent for the wiring.

My ideal solution would be to copy the OEM part on the horn that plugs in. But that's pretty hard to do.

I guess I'll just stick with e-tape, but even then, I'm reluctant because e-tape has a nasty habit of leaving black gunk after a while and of course, un-sticks itself sometimes.