The proper running light circuit will be a brown wire.

Most trucks with a step bumper had two lights, one on each side.

Some of the aftermarket lights only have one wire, so they need a good ground to the bumper for them to work.

Some lights have two wires. One of those will have to be bolted to the bumper or frame to get a ground and make it work.

 

Ok the light I have only has 1 wire.So by screwing it to the bumper (it has 2 screw with it) if done correctly it should be grounded?And then hook the wire from the light up to the proper(brown) it should light up.

 

Yes. The bumper needs a good connection to the frame, and the frame needs a good connection to the battery negative. From the factory they all have this, but as the trucks get older, modified, and rusty(or cleaned up and well painted) they can sometimes lose these connections.