My question is the're 3 wires running from the firewall back to the tail lights. I'm guessing that one is for the licences plate, and the 2 others are for the tail lights. I have a new plug w/ 3 wires running from it, and the ones that are on there now have 2 wires. I'm having some confusion on the electrical. This problem is only when my head lights are on, the left when doesn't come on. I've tried putting the passenger side in the left side, still no light. Any help is greatly appreciated.