Bill, you are correct in that the control box operates relays from the fob. How many lights did you want to turn on? Are they on different switches in the coach?
You should be able to use a volt meter at the control box and find pairs of wires that will be hot (12+ volts) when you energize it by the fob. If you find that the pair is only hot while you are pressing the button then you will need to go through a latching relay controlled by the control box form the fob. This is most likely what you are going to find and the other button will energize another relay that will be used to unlatch the latching relay opening the circuit to the light.
Do you understand electricity and are you comfortable in working with it? If so and you want to design this circuit, let us know and we can help you out.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7