Hey again.
Lastest update.
Got my new downlights. 4W. Tryed the same setup, with the one resistor that dident work (Got overheated) but this time it worked, supect i did something wrong in the old setup. Anyways, it fixed the light problem i had. But i have gotten a new problem.
I have added something to the design (see the attaced picture). A PWM controll board, to get more controll of the PWM output. But when i conect this to the setup the driver of the LED starts to make a worring buzzing sound. If i set the PWM frequency down to 50hz it dosent make any noice (but the light flickers). but if i turn it up to 500hz that are more normal it makes this sound. I suspect i have made something wrong with the grounding, maybe you can see the problem.
FYI: the PCA9685 is a readymade board, so the ground of the board is likely directly conected to ground both ways (to the audrino board and to the drivers ground)