Troubleshooting Magnetic Tow Lights Staying Bright with Running Lights On

Question:

Trailer lights not working properly when headlights turned on. Getting ready to tow a car on a dolly behind my class c RV for the first time. Will be renting the tow dolly. I have magnetic lights to put on the car trunk. Tried plugging those in today to check them, including the wye thatll allow magnetic lights plus the dolly lights though theres no dolly yet. Brake lights and blinkers work fine but when I turn on the headlights, the mag lights go bright and dont respond to blinkers of brakes, just steady on bright. Im concerned thisll happen when I get the dolly, or will getting the lights grounded to the dolly fix things? I like to have RV headlights on even during the day. Im using a 7 pin to 4 pin adapter plus the wye, though I can take the wye out and theres no change.

asked by: Jim S

Expert Reply:

Magnetic towing lights, like the Optronics # TL21RK, are pretty straightforward so troubleshooting will be pretty easy as long as you have a test probe, like part # PTW2993, and access to either another 4-Way or 12V power directly.

Start off by plugging in your magnetic lights into another vehicle 4-Way preferably without using your adapter. If the lights work then you know something on the motorhome side is messed up, but if the lights work in the same manner then you either have some loose wring inside the lights or the wiring connector might need to be cleaned.

If the issue is on your motorhome side then you'll need to check to make sure your adapter is working correctly and that your connector ground is secured to a clean, bare-metal surface.

If you're still having issues after all of this troubleshooting please let me know and I'd be more than happy to help further assist!

expert reply by: Jon G