Troubleshooting Trailer Running Lights Not Active 2025 Nissan Frontier
Updated 12/15/2025 | Published 11/29/2025
Question:
We have a 2025 Nissan Frontier SV without factory trailer wiring, the newest in our fleet of 6 tow vehicles and 3 trailers. Using your wiring harness item 118266 does not activate the running lights brake lights and indicators work. All tow vehicles have RV 7-way plugs we use a 7-pin to 4-pin converter because none of the current trailers have electric brakes. All lights of all trailers work properly all tow vehicles, except now the Nissan. What is the problem / resolution?
asked by: Edwin
Expert Reply:
Hey Edwin, this is a known issue with certain Nissan models. A lot of times there will be some wiring already in place but no relays. The Tekonsha # 118266 comes with the necessary relays as well as the 7-way plug but sometimes there still is a missing relay for the running light circuit.
The Curt Relay Kit # C57000 would be what you would need for that. You will need to refer to your owners manual for the exact relay location. A lot of times it is behind the passenger side kick panel or under the dash on the left of the steering wheel.
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Edwin
12/12/2025
Thanks for your help. Turns out the error was on me. The paper instructions for the wiring kit 118266 were not clear, or I did not read it thoroughly. I installed the hitch and hooked up the wiring to the truck at the back, but stopped there. My day-time testing showed that stop and turn signals work so I considered the job done. I thought the other wire harness and the 3 relays were for a brake controller and charging the battery in dual axle trailers with electric brakes, which I don't need. I even labeled the package "brake controller for Nissan" and shoved it in a drawer to revisit in case of future ownership of a dual axle trailer. A few months later when using a trailer at night, I realized the running lights didn't work, hence me reaching out here. Your comment "...# 118266 comes with the necessary relays..." was key. I found that harness and relays. My lights came on. Connecting it to the Nissan's wiring at the passenger-size footwell was a breeze, and now the trailers' lights come on too.