No brake lights

[Eyesofice43]

I recently bought a 2020 Forest River Alpha Wolf trailer... later found out that the brake lights and turn signals don’t work. They did a piss poor job on checkout with us at the dealership. I’ve already checked my truck’s fuse box and not finding a problem within. Any other ideas? Thanks

[dbledan]

What are the symptoms? Does not work at all or sporadic? Left right or running? Do brakes work?
What truck? Sorry didnt see it your profile but perhaps irrelevant.

Typically it's the ground on the trailer from my experience. You can also check the junction box under the a-frame where the wires splice in to see if things are even hooked up.

If you have a tester you could see if the truck is sending power but depending on the truck will vary the answer as many now will cut power for some. If no test light or meter you will need one.

Sorry for the vague answer and more questions but that's what it takes to answer.

[Eyesofice43]

I have a 2018 Ford F-250. To my knowledge..... maybe brake lights never worked when I left lot as they weren’t great going over everything with me prior to leaving.

[Flybob]

Check your users manual. Most TVs have a separate fuse set for the trailer connector. If you have a meter, check the connector and see if there is power there. Could also be a bad ground connection.

[dbledan]

under hood fuse box, number 26--30 amp is for trailer tow. Number 29, relay, says trailer tow lamps. Your owners manual should verify this. See attached picture.

If you have a meter a test light or even a test plug with lights you can check them.

The 2018 should also have a trailer menu on the dash that will test and show the trailer lighting working or throw an error.

Without a test light the fuse and relay are the first place to start. With one check the plug even if it means a different trailer or accessory to test.

[dbledan]

Originally Posted by Flybob

Check your users manual. Most TVs have a separate fuse set for the trailer connector. If you have a meter, check the connector and see if there is power there. Could also be a bad ground connection.

You can test the trailer lightning by putting a fuse (best) or wire between pins 3 and 4 on the tailers plug. Assuming your battery is charged and not shutoff you should get the running lights on the trailer to light up.

[Bama Rambler]

Just expounding off what Dan said. A lot of times the fuse (#26) is missing and the relay (#29) is not plugged in and is left in the glove box or owners packet.

[tomkatb]

Sit down near the tv plug and get the voltmeter out.

As it is everything likely it is the truck!

[WTP2]

I had a similar problem and traced it to the junction box mounted on the frame. I had to do a little modifying to their wiring set-up. I'd check there first.