There are are actually 3 electrical
systems on your Scamp, separate but interconnected: (1) 12V chassis wiring- running lights and brakes- powered from your tow vehicle via the connector at the bumper, (2) 12V coach wiring- lights, fridge
, water pump, roof vent fan- powered from the trailer's battery OR from the converter when you plug in the trailer's power cord, and (3) 110V coach wiring- fridge
, A/C, wall outlet, fluorescent light- powered when you plug in the trailer's power cord. "None of the lights work" is a bit vague, since all three systems have associated lights.
First step is to test each of the three systems separately.
For the 12V chassis wiring, it would be helpful to connect your trailer to a vehicle with a known-working 7-blade connector. Alternatively, you will need to use a tester to determine which side is not working. Wouldn't hurt to clean the connectors first. EDITED- I misread your post at first.
For the 110V coach system, connect the trailer's power cord to an outlet. Plug in a fan or hair dryer to the power outlet inside the trailer. If it doesn't work, check the main breaker inside the streetside dinette bench. If it does, test the other 110V appliances: fluorescent light
(on AC power), A/C (if equipped).
For the 12V coach system, first leave the power cord plugged in and try the 12V lights and vent fan (if equipped). Then disconnect the power cord, make sure the coach battery on the tongue is properly connected and clean, and again test lights and fan.
Come back and let us know exactly what works and what doesn't.
Could be something simple like breakers/fuses, a disconnected ground wire, dead battery, or dirty connections, but if it's more than that, it may be time to bring in a professional. Diagnosis of electrical
faults takes time and being conversant with the use of a multi-tester. Correction of problems requires knowledge of codes. Mistakes can be dangerous to person and property, and you're working under a time crunch. Unfortunately, this is exactly the time of year when a lot of RV repair shops are swamped with work.
An auto repair shop or U-Haul
could at least work on the chassis lights and connector part to get you on the road safely. I agree with Paul that the lack of working brakes is a problem, though. California requires brakes on any trailer over 1500#, and your trailer is going to be a lot heavier than that once you load it up with food and gear, typically 2400-2600# for a Scamp 16. Since your vehicle only has 4-flat wiring, connecting the brakes will run several hundred dollars for the controller and wiring upgrade. In addition, the brakes themselves should be inspected and serviced.
What is your tow vehicle, BTW?