I have a 2015 Civic with a trailer hitch that was installed by U-Haul when it was new. I’ve hauled trailers three times, one on a 1,000km drive and never had any issues with the lighting.

Last week I rented a U-Haul trailer for a local move (total of like 15km) and noticed that the lights on the trailer would dim a bit when the hazards or turn signals or brake lights came on, as if there wasn’t quite enough power.

Then, the turn signals just stopped working.

This problem continued after the trailer was disconnected.

I’ve tried replacing the fuse and unplugging and reconnecting the relay.

My next step is going to be to purchase a new relay to swap out the old one, but would appreciate any other suggestions or possible causes.