Gary, your front and rear marker lights should be on the same circuit from the headlight switch. I would start at the front marker lights and see if you have 12 volts to the lights themselves. Use jumper cables or a line from the battery ground terminal to verify power. If you have not power to them, start trying to trace the wiring down by going behind the TV, as not many manufactures insulate the front caps very well, and you may be able to see/trace the wire from there. It probably runs down the drivers side pillar to the switch. You have a large RV dealer in your town. If you go to the service department and explain what you have and are trying to do, they may be able to give you a print-out of the wiring for you MH.