I checked the light bulbs on all four corners and they all work: brake lights, flashers, markers. I check and replaced fuses, and I thought that I replaced the relays, but the horn and turning signals still didn't work. Then I changed the switch in the steering column, which was a major PITA. Still no horn or turning signals. Any ideas?

Signed, Perplexed

Electrical "gremlins" are an absolute P.I.T.A..  I've never been good with electrical things so very frustrating when I have to try and sort them out.  All I can add is to say is to chase as many of the connections, connectors and even the wires as you can to make sure they are solid and, good luck...!!!

I had an 81 and the horns didn’t work 12 v applied to each to test 

replaced defective horns, ( not Easy to do)

got Continuity to horns when pressed, but had to replace the horn relay to make it operate properly.

The original horns with toast

larry

 Check the relay in fender well, jump the I believe green wire there if horns work that is your culprit 

Thanks! I will try that.