[03OVERLAND]

Already been through the issue left blinker hardly ever worked, popped open the (blue case) flasher relay and re-soldered certain joints as shown in JeanLuke's - Flasher Relay Repair - post. SUCCESS!. Still working yonks later.
Thanks JL, excellent pics and detail to access the relay unit and repair it.

Unfortunately I didn't have a device handy for pics of the following, so referring to that post may be helpful.

The issue; (I think not related, just coincidental); Left blinker started the annoying habit of starting to blink then just staying on solid not blinking and WON'T turn off under any circumstances, even with the car parked and key out. MAY turn off by itself hours later, or have to disconnect battery until it settles. Even then may stick again the very next left turn. Frustration is an understatement. Got tired of this and popped the flasher unit again to examine its delicate insides. 2 solenoids inside, identical, one nearest the pins end is apparently for left turn. Poking around with miniature screwdriver I determined that the hinged plate carrying contact points on the solenoid can often stick in the down position despite the return spring. I don't know why, there seems to be tolerance although it is fine. As long as I was accessing it the slightest touch with the little screwdriver would release it again, so it must be just a touchy thing.
The contacts are open when the plate is down. I had no other flasher function while the plate was stuck
Note; this is purely a mechanical binding issue, nothing to do with electrics, earth, electromagnetism, bulbs, fuses, steering column control etc.
I used needle-nose pliers to carefully and gently but with subtle firmness to manipulate the tiny hinge plate in its slots to free it up a little in case any tiny burs were present in the slots, followed by a couple of VERY TINY drops of engine oil tapped on with the end of a toothpick. I seemed to be unable to make it stick again after that. Reassembled everything and left turn has been functioning normally and reliably ever since. Same problem has been known to occur with right turn for some people apparently. Same fix most likely.