[Harkon]

You took the orange lead from the indicator and tied it to ground?

If you can, disconnect the indicator light all together. What happens then? Which diodes did you use? Should likely start with a 1Nxxxx number.

The cathode of the diodes (the end with the stripe) must go to the lb wire on the indicator light that has been disconnected from the lb wire that connects the switch to the right signal lights.

like this
the red x is where the wire gets cut

 

[Harkon]

The O and LB wires you are showing in your picture. Are those going to the indicator light or are they connected to the indicator light right now?

Where do the other ends of the LB and O wires you cut go to? Does the dash indicator work as expected?

The kit you pointed out looks like this;

The kit you show has the diodes separate. Not that that matters, but in that case, the red wires would go to the LB and O wires and the blue wire to the LB wire to the indicator. Then the O wire on the indicator is tied to ground, presumably with the black wire. My bet is that if you take the incandescent bulb out of the front, (do you still have incandescent in the front?), your LED will be as bright as the left side. In that case, you are still back feeding, somehow, through the indicator. I'm not sure how, but if you have an ohm meter, put it across the LB and O wires in your picture. If it doesn't read anything, or infinite rather, then put your meter on the diode setting. You should read infinite there as well.