Classic led lack of voltage issues. White requires The most voltage. The more it drops The mord towards red color then flicker and nothing. If you have flicker but decent voltage, it's probebly The data line..

I asked in Another thread whats on thoose boards, if it aint to much other stuff you can probebly wire it and skip The board.

Are Therese two on the same board?

Maybe follow The wiring with the voltmeter and see if you can locate The drop.
Is this a singel led?
If it is and it produces more then one color, there should be three or four wires connected to it, which is important. If there is three, you should be able to lend twelve volts somewhere. If there are four, you pretty much need to find why and where it is dropping.