This is not a question, but for the information of those who might have a similar problem in the future.
Many years ago I added a 4-way flashers circuit to my Valk using Chet's instructions on the Rattlebars sight:
http://www.rattlebars.com/mtz/fourways.htmlYesterday I had cause to use them (as I have often before) to offer help to a stranded motorist. The motorist was fine, but when I switched the four-ways off and signalled to get back on the road, my left and right turn signals flashed together and the yellow indicator on the headlight bucket didn't work.
I had been noticing my turn signal switch getting stiffer over the last couple of years with the intention of eventually getting around to cleaning it and lubricating it, so this was the first thing I did after I got home.
I took it apart, cleaned everything with aerosol electronics cleaner, put dialectic grease on all sliding surfaces, and reassembled it.
Everything now works properly.