One horn stopped working

[edb]

Hello all. This is a head scratcher. I have a 1972 E3 Bavaria. Totally stock. The right side horn stopped working the left works fine. I did all of the usual terminal cleaning, bench tested the non-sounding horn on a spare battery and it works fine. I attached a test light to the right side horn spade terminals and it shines bright when I press the horn.
Does anyone have any thoughts?

Here's pic. I'm finally winding up a 9 year restoration project.

 

[jmackro]

Perhaps it isn't properly grounded. If it bench tests OK, and the feed wire is hot when you press the horn button, there isn't much else left to go wrong.

 

[Arde]

I would swap left and right horns and see what happens.
Nice car!
PS: I thought nobody uses horns in MA.