Anything special for grounding running lights?

[Jemo]

I have a newly painted truck, getting everything together and am pretty sure I have a grounding issue with my running lights. They're not real bright in the first place and I notice when I leave the lights mounted in the grill bar and lean it over to touch the bumper, the lights get about 50% brighter....still not as bright as they should be but this tells me there must be a grounding problem. They're mounted in the grill bar and the grill bar screws into the painted panel behind the grill. Not sure if I should run a ring terminal to one or two of those mounting bolts and bolt the other end of the wire to the frame or what? Is this common? How did others fix this?