Troubleshooting Trailer Running Light Circuit of 2012 Nissan Titan Not Being Active

Updated 06/18/2025 | Published 11/30/2021

Question:

I am unable to get tail lights to work on trailer. I have stop/turn/flashers, but not running lights. I know the problem is on the vehicle side, but cant find a fuse or relay that operates the tail lights. its a 2012 Nissan Titan. Any ideas?

asked by: Benny C

Helpful Expert Reply:

Under the dash of your 2012 Nissan Titan there is a relay harness that you will need to check. The top blue relay would be the running light circuit. You can easily test to see if it's bad by swapping one of the nearby blue relays into it's slot to see if the problem goes away (it will then move to a different circuit since the relay is bad).

If you need to replace it, you can use one of the blue relays from the Curt Relay Kit # C57000.

I attached an install video that shows trailer towing relays installed on a similar Nissan Titan for you to check out.

expert reply by: Jameson C

Tmnt

6/18/2025

What would you suggest if it was a 2012 nissan titan and the tail lights work, but not the turn or brake lights? I have changed out the two blue fuzes on the left behind the battery already. Last time I tried this i wana say they weren't getting power and changed out the 2 blue and brown and tan fuze. And at that point gave up to being in over my head. So would that be an upstream relay or fuze I would greatly appreciate any pointing directions of wich way to go next.

Jameson C.

6/18/2025

@Tmnt Sounds like you changed out and checked the relays associated with trailer wiring but did you check out the fuses as well? Basically the relays provide the power for the circuits and the fuses protect the circuits. If either is bad the circuits won't work. Did you check for corrosion on the pins of your trailer wiring connectors as well?

Tmnt

6/18/2025

@JamesonC checked it out better than the pizza delivery guy on the plugin. But didn't realize there were also regular fuzes in the mix.