If the bulb was shorting, it would blow a fuse.
Okay, lets start over. I attached the portion of the wiring schematic for you to see. Now, according to the schematic, there are two brown wires, one to each of the two lights. Then, there are two black to ground on the frame.
If you are getting power to the brown wires and you have a good ground, I cannot see how it does not work unless the sockets are bad. I misunderstood earlier. I thought you did not use the new socket.
What I want you to try is this. Make a long jumper wire that will reach from the black ground wires from the lights and run it directly to the negative battery terminal. If they work, you have a bad ground. I realize you have cleaned a new ground, but it may fail under a load. This way we can confirm if a good power supply is going to the light. If it does light, we need to make a new ground. I cannot tell you how many times I would check continuity for ground and it checks good until a load is placed on it.
Try this and let me know what happens.
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Saturday, November 24th, 2018 AT 8:00 PM