Brake Lights on Vehicle Light Both Brake and Turn Signal Lights On Trailer

Question:

Hello, I installed part: HS381-9000 onto my utility trailer. When I plug it into my 2014 Tahoe, only the right light illuminates. These are the following diagnostics. 1. Press the brakes all the light including amber illuminate. 2. Turn on Left turn signal nothing 3. Turn on right turn signal all the lights blink including amber. The Tahoe has the factor 7 pin connector, when I use a 7 pin-4 pin converter, and plug in my magnetic trailer lights, the lights function correctly leading me to believe that issue is not with the vehicle. Does this sound like I have wires crossed, or a bad ground on the trailer? Thank you for your help.

asked by: Andy

Expert Reply:

Thank you for describing the problem you are having with your trailer. I noticed you said that the amber lights were on with the brake pedal applied. Are you referring to the amber lights on the vehicle or amber lights on the trailer? If they are on the vehicle then you would need to take it to an automotive repair shop for inspection but if you're referring to them on the trailer then it sounds like you have a separate lighting system which means the brake and turn signals are on different circuits.

If you do have a separate lighting system on your trailer then one of the issues you are having could be that you are not using a converter to isolate the brake and turn signal circuits. The 7-way on your vehicle that is used to power the trailer lights will have the brake and turn signal circuits combined therefore you will need to do this on your trailer. In order to isolate the brake and turn signal circuits, I recommend using the Vehicle to Vehicle Tail Light Converter part # 118158. This will need to be installed in between the junction box and tail lights on the trailer.

The other issue I think you are having is that some of the wires are crossed. Please note that when wiring a trailer you will need to test each of the tail light wires for function as matching colors can cause too many errors. In order to test the tail lights on the trailer for function you will need to apply a 12 volt power source to each and then check to see which light is illuminated. The junction box and converter box both list the correct function/color for you.

expert reply by: Conner L