Utility trailer lights

I've ruled out that it is not a ground on the trailer. I grounded it in three separate places on the frame of the trailer, and I checked the fuse and the relay under the hood in the truck and they're both good.

The brake lights come on when braking, and they work with turn signals and 4-ways. But no running lights.

Is there anything else on the truck that can cause me to not have running lights on my utility trailer?

I bought my trailer used and the lights worked on my way home. I wanted to rewire it because it was wired very sloppy. I'm good at wiring, and it is simple on a trailer. Just match up the colors.

I spent hours getting rained on trying to figure this out.

2021 TRD Offroad

 

Have you checked the running light pin on the trucks trailer plug?

 

I'd check the black trailer harness plug end for corrosion

 

Welcome to the forum

Grab one of these testers at auto parts/TSC/HF for a few dollars. It is an easy way to insure your truck wiring is working.

 

if you haven't done it already, take the tail light lenses off and check all the bulbs and sockets for corrosion.

most trailer lights are cheap stamped steel inside and can rust and loosen up with age and vibration.

 

Friend with a 2011 Ram borrowed my trailer, when he brought it back lights didn't work so we cleaned connections to no avail. Hooked my truck up and my trailer lights all worked so, we hooked his Ram up to his trailer and all lights worked...

 

i second this. first verify the truck. or take a set of wire leads and jump straight off a tested-good battery to the trailers plug.

 

I've noticed corrosion already on my truck 4 pin connector after just one year. Not optimistic how long it will last...

 

Thanks guys. I really appreciate your responses.

I just got the tester in the mail and tested it today. The "tail" light on it isn't coming on. So I guess the problem isn't the wiring on the trailer.

I guess the problem lies on the truck somewhere.

I'm pretty sure I remember the running lights being on when I bought it... but I could be wrong.

I do have aftermarket tail lights from tacomabeast. Don't know if that'd cause an issue.

Under the hood, I checked the fuse and swapped the relay for the one for the horn. Looks like they're both good... I also checked both plugs on the back of the truck using a 7 pin to 4 pin adaptor.

 

well its a strong possibility given the low quality stuff they sell

 

Well... mystery solved. Turns out that there's more than one fuse for the towing. There's a relay and two fuses in the fuse box under the hood.

It was the 30amp fuse labeled "towing tail." Face palm.


Yesterday, I was looking at all sorts of threads for tacomas and tundras coming up empty handed. One said that on the 2nd gen there's an inline fuse behind the driver tail light and another about a box under the driver seat. Nothing there on my 3rd gen.

This morning, as I'm drinking my coffee, still looking for a solution on the interwebs... I find a thread with the exact issue on a 3rd gen. His solution was the fuse. He posted a pic of the fuse box diagram, and I saw that there's two fuses. I then went out, popped the hood and Holy crap. All this frustration over a fuse in the fuse box that I didn't see.

Thabk you everyone for your responses. You guys are awesome.

 

"All this frustration over a fuse in the fuse box that I didn't see."

At least you learned this in your own driveway instead of in a rainy parking lot with a flashlight 150 miles from home.

Glad it wasn't something expensive, keep that tester in the truck.
Call it a win!

 

glad you found it! a whole lot cheaper than it cost me for a similar mistake!!

in 2007-ish, i had recently bought a new-to-me 2001 mitsubishi eclipse. as i do, i gutted the interior to install a sound system. something happened somewhere, and trying to test my newly-installed sound system, the entire cabin was electrically dead. no lights, no windows, no blower power, no radio. i looked through the under-hood fuse box. i looked through the in-cabin fuse box. i spent all of a sunday on this after spending all saturday on installing all the gear.

finally, i give up and drive it to the dealership for them to figure out. with only the drivers seat installed, an open dash, no door panels, and no center console.

they had it fixed in minutes, for a grand total of $180. the result? 1-10A fuse.

turns out the mitsubishi's have a little yellow block in the underhood fuse block that hides 2-10A fuses. this block is referred as the 'shipping block'. during transit from the plant to the dealer, that block is pulled out, and it keeps all the creature comforts from coming on. i had checked every single fuse, except those in the block because i couldn't see them in there!

 

Omg that blows. The fuse I mean.. but the $180 bill at the stealership really sucks too.

 

I understand that you have to (and should) pay for the knowledge not the job -- those guys really... I won't go as far as saying took advantage, but certainly showed no compassion.

 

i took it as paying for the knowledge.

for the next 4 years, i was on the eclipse forums and helped point countless people with the same issue to the right fuse location. so in a way, it paid for itself, just not for me!