LED License plate lights splice?

[Slemmy]

Have a couple of LED license plate lights. Each has a red and black wire coming out. I’m assuming red will be the lead that I should splice to the running lights (so they come on when the lights are on), and the black will go to ground. There is a green wire and a black wire going to each tail light. Any suggestions on which wires I should splice these suckers on to?

Thanks!!

Erik

[AcampoDave]

Slemmy, get yourself one of these https://www.harborfreight.com/circuit-tester-30779.html they are widely available and worth every penny. You can quickly use it to determine which wires are hot and which are grounds. I actually found mine to be so useful I bought a high quality one that even makes a beep when the circuit is complete for those times when it is difficult to view the light. (I.e. testing brake lights) As to your specific question on a vehichle, black is the factory color used to indicate a ground.

[hotrodder]

Green is the power feed for the taillights, black is the ground. I have them on my 65 GMC