Though connections may work with the higher load from incandescents, the LED lamps may not draw enough load to overcome dodgy connections/poor grounds. Best to try running a separate ground line to at least each of the lamp stems as a test. Also note that your new LED rated flasher should still work fine with incandescents...so you can test it while your have incandescents fitted.
Next....Dedicated grounds on all four bulb sockets. As soon as I add the third LED things go south. With 2 LEDs in the rear, 1 in right front and incandescent in left front.
So to be clear, you will need the tweaker in place when trying to run LED's on a bike with a single warning light (b/c this sort of warning setup passes a low current through the incandescent warning light bulb when operating...insufficient to light up the "off" side incandescent lamps, but plenty enough for the low load LEDs....so you get both right & left sides flashing. The tweaker should also work fine if all four lamps are still incandescents, just unnecessary. So correctly connect twaeker for these tests. Confirm it works with 4 incandescents first. Then try all LEDs and report back.
Reporting back....
The test light is providing enough current flow to ground to make the flasher trigger on and off. It is doing what the actual switch does, but with its test bulb adding in resistance. Probably would not do this with incandescent bulbs as they need a lot more current.
Yes, I have the L terminal connected to the load side .
Yes, that sounds like a good idea, although at this point I'm tempted to ditch the LED signals idea....
LED or normal incandescent bulb?
For an incandescent bulb, the brake (brown) and tail lamp (brown/green) wires could be crossed over.
The brake light at the first key position would work but at reduced (tail lamp) brightness.
Or, perhaps one feed and the ground wire are crossed over?
