Your trailer tailights are dual-filament, with one being the running lights and the other the brake lights. You need a separate power source from your towing vehicle's brake lights to power them. The easiest way to do this is go to U-Haul and but a set of their trailer towing taillight bulbs for your towing vehicle. The bulbs replace your standard tail/brake light bulbs, and they have two wires coming out of the base of the bulb. One of the wires connects to your trailer's running lights, and the other one connects to your trailer's brake light circuit. I'm trusting that when you re-wired your trailer, you ran two wires from the taillight socket, one for the running lights and one for the brake lights. In some trailers, the brake light circuit also doubles as your turn signals. Good Luck.
check for power at the trailer connector.
Are you getting power to sockets? Make sure you have a good ground circuit
Take a light tester and check the pins at the truck side trailer plug. With the truck set for running lights check for power at the pins. If there is power then there is a loose or bad wire on the trailer side. If there is no power then there is a power problem on the truck side.
First understand the wiring. It can use four to seven wires to control lighting. Choose the correct connector. Connect all the necessary components to work simultaneously such as electric trailer brake controller, backup lights and a 12V power supply. Take the vehicle to an expert if the task is tricky.
The center pin of a seven blade trailer plug is for reverse lights, not power. What type of truck is it? What trailer plug do you have...
The Control Unit and Harness are strongly recommended if you are going to tow anything that requires lights/brake controls. FYI, you don't have to get HONDA control units, most businesses that sell trailers sell various name brands and can do the wiring for you. Anyway, the wiring for the taillights and brakes lights of the vehicle are not strong enough to carry enough power to supply the electrical on a trailer (very dim-could cause a short). The Harness connects a power source (battery) to the trailer wires. The Control Unit is connected to the vehicle wiring as well as the Harness. When you step on the brake pedal, the Control Unit senses it and allows the power to go to the proper wiring on the trailer directly from the power source, therefore you will have brighter lights on the trailer. The same for parking and turn indicators. This is worth the money. I have this set up on my 2003 Odyssey.
When you turn in a tractor trailer (or any vehicle with a trailer), the tyres of that trailer aren't going to take the same course as the tyres on the power unit - they'll go within the turn radius of the power unit. Drivers need to be aware of this, as this can cause the trailer to hit things the power unit would clear, such as curbs, utility poles, etc.
If you have a 1998 or newer it could be a fuse in the power distribution center under the hood. The whole trailer light system is fused through there.
Primary brakes are situated at the front wheels and provide about 70% of a vehicle's braking power. Your secondary brakes are located at the rear wheels and only provide about 30% of a vehicle's braking power.
Make sure that the wiring harness is properly grounded. Baring that, there is probably a short in the wiring somewhere. A short means the two wires used in trailer lighting are touching someplace.
To convert 12 volt trailer lights to 24 volts, you would need to install a voltage step-up converter or a voltage doubler circuit in your trailer's electrical system. This will effectively double the voltage to the lights, but make sure you choose a converter that can handle the power requirements of the lights and wire it correctly to ensure proper functionality and safety. It is recommended to consult a professional electrician or mechanic for assistance with this modification.