CM370z

I wonder if any of y'all can help me find where I messed up. The instructions are simple enough but for some reason, my fog lamp starts to flicker on its steady mode about 5 minutes into driving. I soldered the red to red, white to orange (reverse), and grounded the black to the factory ground behind the driver side tail light. It still flickers. So I ended up switching to 18 gauge wiring instead of the 16 gauge evor provides. It still flickers. So I ended up wiring it to the other tail light, still flickers. I changed the grounding point to another hole I found on the chassis, still flickers. I cannot for my life identify the problem. Please help, it only starts to flicker after a little bit of driving. It doesn't flicker right when I turn it on after letting the car cool down. Should I try splicing the ground wire into the tail light ground wire?

Edit: I know it's not the light itself because Jay from EvoR ever so kindly sent another one as we thought the first one was broken in some way and after wiring the new one in...still flickers

__________________