See full version: Troubleshooting Trailer Running Lights Staying On when Vehicle is Turned Off
There should be no signal when the lights are off, and a signal when they are on. If there is a signal with the lights off, then there is a problem on the vehicle side. Check to make sure that the brown wire is properly connected to the running light wire at the rear of the vehicle and that the white ground wire is attached to a bare metal surface that is free of dirt and corrosion. It could also be a bad converter.
To test a converter, you will need to first test the wiring going in for function. If the functions are incorrect going in, then something is mis-wired and you will need to start again as if installing the unit for the first time. I have included a link to the installation details for the # 119179KIT below for reference. Depending on the vehicle, you may need to pay special attention to the directions regarding 2 wire and 3 wire systems and install according to the wiring on your vehicle.
It sounds as though there is a short or something is mis-wired. Using a circuit tester, like the Quickee # 3808, check the connection points in the vehicle side connector, to see if there is constant power on the running light circuit (brown wire on the 4-Way) when the vehicle and lights are turned off.
If the functions are correct going in to the converter but incorrect going out, then there is a problem inside the converter and it will need to be replaced. If the signals are correct going in and coming out, the issue lies elsewhere. I have included a video below, on testing a converter, that should help.
asked by: Leroy
I have the trailer white wire hooked up as the ground wire. no lights work unless that wire is connected. all lights are now working however the tail lights and side running lights stay on all the time . I have tried the brown wire from the trailer to every wire and only one wire from plug will turn lights on but that is the wire that keeps them on constant
This sounds like the problem could be a short or possibly ground related but based on what you have said a ground is much less likely. Look for any pinched or frayed wires on the trailer and fix as needed. This could cause a short resulting in constant power draw. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light.
Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.
If the connections inside of the trailer connector look good and there is no corrosion or wires touching each other, then start at the right tail light with the trailer battery attached and test for the brake and turn signal wire using a circuit tester like part # 40376. It will be the only wire with power running through it. Follow that wire toward the front of the trailer looking for any damaged or frayed sections that may be making contact with a circuit that is powered by the trailer battery.
It sounds like the power from the trailer battery is somehow reaching the right brake and turn signal circuit. The brake and turn signal circuit on the trailer should not be connected to the trailer battery. here
asked by: Joe H here
I have a strange problem, the right tail light stays on the trailer when my vehicle is unplugged. It started when we moved the trailer with a bobcat and the lights werent even plugged in. The only way I can get it to go off is to take the 12V battery out. Seems strange, any ideas? Thanks
The first step I would take is to check the wire connections inside of the trailer connector. On a 7-way trailer connector, the pin for the 12V battery power is right next to the pin for the right turn and brake signal. If these two wires are touching, then that will explain why your right tail light is constantly receiving power. I have attached a photo showing the inside of a trailer side connector. [links]
I would also recommend inspecting the rest of the wiring on the trailer just to ensure that there are no other areas that are damaged or that could likely cause problems. I have attached an article on trailer wiring that should help while troubleshooting this issue. If these steps do not help you find the issue, then let me know what you come up with and we can take further troubleshooting steps. [links]
If the tail lights are illuminated even after you have used the on-off switch to command them off, that means the switch supplying power is fused shut and/or the circuit is being powered when it is not supposed to be due to a wiring fault. To resolve an issue such as that, the circuit powering the lights has to be traced, starting with the devices that should indeed be "off" if commanded off (such as the light switch, relay, etc.). If the brake lights are not functioning, it is possible the filaments in both bulbs are burned out and that possibility should be ruled out first. If the bulbs are OK, the brake light switch and the rest of the circuit will have to be traced. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an electrical circuit diagnostic and the responding certified mechanic will get this problem resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
My car has 120000 miles.
My car has an automatic transmission. here
My tail lights stay on even after car is off. The hazard lights and turning signals all work but the brake lights do not. here
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