Trailer light question

[marshman]

I have a new utility trailer I bought last summer. It came with LED lights. This morning while going to the lease I crossed a railroad track and immediately noticed my side marker lights and taillights went out. I’m pulled over when I could and checked connections and looked for anything obvious but didn’t see anything. Trailer turn signals work and brake lights work jus tree running lights are out. Any suggestions on what to check next?

[Snowflake Killa]

My guess would be a ground wire

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[PYBUCK]

Not a ground or the other lights wouldn't work. Check your trailer light fuse, that was what was wrong with mine, blown fuse.

[bignick612]

Not a ground or the other lights wouldn't work. Check your trailer light fuse, that was what was wrong with mine, blown fuse.

This is what happened to me also. Fuse on the truck was blown and still had brake and turn signals but no running lights.

[Big Lee]

Likely the trailer light fuse.

[marshman]

I’ll check the fuse. Hopefully it’s just that.

[Quackerbox]

Could be a ground to the light itself.

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[bboswell]

Get a tester and see if you are getting running light power to the truck plug

[DawgOnIt]

fuse #99 if it's a late model Ford F250 or F350. Had a direct short on a trailer I finally found, so got familiar with that fuse. IT IS A FORD mini-fuse (30amp), not just available anywhere.

[WItoTX]

Check grounds. Those side marker lights often have just a crappy thin metal tab that touches the metal. It doesn't take much to get corrosion between the trailer metal and that tab. I'd bet those marker lights weren't working before you hit the tracks, you just noticed it then.

[marshman]

Check grounds. Those side marker lights often have just a crappy thin metal tab that touches the metal. It doesn't take much to get corrosion between the trailer metal and that tab. I'd bet those marker lights weren't working before you hit the tracks, you just noticed it then.

No sir they were working. I can see the side lights from my side mirrors.

[Rick]

is it a 4 wire plug? brake and stop light work off the yellow and green wires, Running lights and marker lights are powered by the brown wire. if it was a trailer ground issue all lights would not be working. If it was a grounding issue at each marker light, it is highly unlikely all would stop working at exactly the same time. do the tail lights on your truck work when you have running lights on? if not, it is probably a fuse, if they do you are going to need a meter to figure out what is going on. Do you know if your trailer is grounded thru the ball, or does the white wire on the trailer plug ground directly to the trailer frame?

[SAC]

fuse #99 if it's a late model Ford F250 or F350. Had a direct short on a trailer I finally found, so got familiar with that fuse. IT IS A FORD mini-fuse (30amp), not just available anywhere.

This, if this.

[softpoint]

See if the vehicle tail lights work. If they do, it's not the vehicle fuse. It's not the trailer ground, or none of the lights, turn signal or otherwise would work. With the tail lights turned on, wiggle the connection at vehicle plug, see if they come on. Very good chance it's either that plug, or the trailer has a short that blew the vehicle tail light fuse.

[Big Lee]

See if the vehicle tail lights work. If they do, it's not the vehicle fuse. It's not the trailer ground, or none of the lights, turn signal or otherwise would work. With the tail lights turned on, wiggle the connection at vehicle plug, see if they come on. Very good chance it's either that plug, or the trailer has a short that blew the vehicle tail light fuse.

Most modern vehicles have a separate fuse for trailers. Vehicle lights will all work.