Trailer Wiring for 2007 Jeep Wrangler Towing Utility Trailer with LED Lights

Question:

re: Tow Ready Accessories and Parts - 118158 Vehicle to vehicle taillight adapter. Sorry if this has already been answered in the FAQs...but I am still unclear. I have a 2007 Jeep Wrangler, regular bulb lamps in the turn/brake lights. The Jeep has a flat 4 wire trailer light connector. I tow a utility trailer with the typical combo brake/turn lights. I am adding Jeep OEM spare tire carrier which has a third brake light. I may add additional turn signals for visibility, but not sure. My questions are: 1. The tow vehicle is regular bulb lamps can the trailers light be LEDs? 2. In what type of configuration are isolating diodes required? are they needed in what I am trying to do? would I need to add one to the third brake light? In regards to #2 above, I do not understand where the power feedback would come from if the lights downstream of the adapter are only connected to the adapter? THanks!

asked by: Don K

Helpful Expert Reply:

All of the 4-pole flat trailer wiring harnesses we offer for your 2007 Jeep Wrangler (shown on the link at right) do not have built-in converters; they pull the power for the trailer's lights directly from the Jeep's taillight wiring.

On a 4-pole vehicle connector the stop and turn signals are already combined; the yellow wire carries left turn and stop signals and the green wire carries right turn and stop signals. The brown wire carries running light signals for both sides of the trailer.

It is permissible for a tow vehicle with incandescent lighting to pull a trailer with LED lighting, but the reverse is not permissible IF the trailer lights are pulling power directly from the vehicle taillight circuits. Incandescent lights draw much more power, and so a vehicle with this type of lighting will have heavier wiring to support the current requirements. An LED-equipped vehicle will use lighter-gauge wiring that potentially might not support the current demands from a trailer with standard incandescent lights.

If your trailer uses combined stop/turn lights then you do not need to use the Vehicle to Vehicle Taillight Converter # 118158 that you referenced, but for the third brake light you will. You do not need diodes for your application with a third brake light. Isolating diodes are needed only if two power sources are supplying power to a single bulb.

If you intend to add supplementary lighting to your trailer then it will be a good idea to use LED types since they will demand less power and reduce the chance of overloading your vehicle's wiring. A link to our trailer lighting page is provided at right along with a helpful article on trailer wiring.

expert reply by: Adam R