hi my 56 f100 with a tilt gm steering column , blinkers dont work unless the test light is being used in the specific wire , creating a ground , obviously , and one side of flasher feed wire to turn wire doesnt have sufficent power unless engine is running , i know sounds real screwy any suggestions
So, they're just not flashing, but they are lighting up? Using LED lights anywhere? With the limited info, I'd guess either bad grounds at your light sockets or a bad/wrong flasher.
Also, if the column has an integrated hazard light switch make sure it is off as it disables the indicators. This had me chasing my tail with my indicator setup for a while.
Fiberglass fenders? Have a separate ground wire? Fresh paint? Have star washers? Try a different flasher? Is it heavy duty? Just a few thoughts to consider.
You aren't joining up the front and rear circuits at the column are you? Front and rear turn signal don't work together, people join them and the first problem is the circuit resistance is all wrong for the capacitor. Then they try the brake lights and things go sideways then.