Weird electrical issue

Got the new blinker relay for The Titanic today. Left signal works fine, but when the switch goes to the right (up) the signal lights do nothing and the pilot circuit (gauge lights, pilot light and taillight) blinks. This occurs whether the key is in the lighting position (2) or just the ignition position(1). All connections are correctly color-connected. The switch appears ok as there's power at the green/white wire when it's flipped, but when it's connected with the green/whites to the individual signals and flipped, it activates the pilot circuit via the relay. I'm stumped.

Green/white feed wire from switch shows dead short with no power. Has to be something in the switch.

I had a fun experience like this recently with my car. It turned out to be because of a poor earth/ground for the light in question – I think it usually does! The fact that other lights came on unexpectedly was just down to the juice taking the path of least resistance, and not because of any weird wiring issues. Maybe that's your issue too? If it were simply because of a short, wouldn't the fuse blow? HTH

Disassembled the switch, cleaned and lubed everything and did some testing with just the switch core. I started tracing back and after I pulled the green/white going to the rear signal, the backfeed stopped. In turn I pulled the wire at the junction behind the taillight and the wire going into the signal shows a short. More on this tomorrow.

I should have incorporated that I pulled the bulb before testing so the power wire didn't have a normal path to ground.

A split piece of shrink tubing allowed a strand or two of turn signal wire to ground to the stalk internally. All good now. I guess it wasn't enough to blow the fuse, but who would have guessed that it could power up the primary light circuit via (I assume) the taillight?

Excellent, well done!