Signal issues

BobW said
Did you change the bulbs to LED's?
Change the flasher to electronic?
If so, you may need to reverse the wires on the flasher plugs. It has to do with proper polarity fo rthe LED's.
This solved the same issue on my '64 Valiant when I switched to LED's, no 4 way involved though.

looks like that was it !! I had driven myself bonkers checking grounds and cleaning sockets trying to sort it out. I reckon the LED indicators were just enough to not make them trip. I’ve since swapped everything over to LED with continued success