Trailer running lights aren’t getting power

I only tow a couple times a year so it has taken me awhile to notice this issue. I was towing my in laws boat back from lake last week and I had no running lights. I have towed this boat before I have always had issues with the lights. I just figured it was the trailer. Today I hooked up to another trailer and confirmed my truck isn’t sending power to running lights through the 7 way plug. I haven’t tried the 4 way plug yet.

How do I fix this? Will Toyota do anything about since it has never worked?

 

Did you check the fuse?

 

I did not because all the other lights work. Brake, signal, flashers.

 

Boat trailer could have a bad circuit which could blow the fuse to protect the truck I want to find the fuse map for this truck to see which one it is

 

your truck light should be protected from trailer lights so that would explain why your other lights are good my old truck had towing fuses in power dist box under hood

 

under hood fuse 6 Tow Tail would be the fuse for your trailer tow lights

 

definitely the fuse i had the same issue .. check owners manual for which one .. they provide an extra one in there to use

 

The trailer lights work just not the running lights. Same story on two separate trailers. I will check fuses

 

Is there a separate fuse for just the running lights?

 

on the trailer yes

 

Just google the diagram for a 7 pin and use test light to check truck. Not complicated.

 

Went and looked at my truck no fuse for Tow Tail I have a blue circuit breaker so testing at the 7 pin is the way to go

 

any update on this? Same issue here 2013 toyota tundra base
I have proven its my truck with a friend plugging into my trailer and running lights work.
I have break, hazards and blinkers nothing else.
Checked fuses
even went and bought another 4/7 and the same thing.
so its from the for prong adaptor to the battery but cant find the issue.

Please Help

Vinny
Tucson, AZ

 

From the diagrams I have, it looks like the tail lights (not brakes or flashers) are tied to the same pin as the marker lights (Pin 2 - Brown Wire). Are your tail lights off as well as your markers? This circuit is powered by the 30A TOW TAIL fuse in the engine bay (battery) fuse box. The fuse feeds the TOW TAIL relay which feeds Pin 2 of the trailer connector. The ECU energizes this relay when the parking lights or headlights are on.

I'd check the fuse and the relay. By the way the other lights and flashers are powered by different circuits than the marker/tail lights. So I'd definitely check the fuse.

 

There are no circuit breakers in this vehicle. The blue rectangular item is a relay. You should also have a 30A TOW TAIL Fuse.

 

I totally forgot I posted this. The TOW TAIL fuse was burned out in my truck. I replaced that and I now have trailer running lights again.

 

Excellent! The schematics solve the problem once again!

 

Anyone have any ideas where to check, I’m having the same issue, I have everything but running/tail lights, verified and swapped fuse and relay, has full voltage at fuse and relay, crawled under the rear and disconnected the wiring harnesses from the backside of the bumper connector and still no power at that pin. I found a work around by modifying my 7pin -5pin adapter, swapped the 12v constant with the running light. Truck is unmolested never crashed or modified in any way. Still under warranty but if it’s an easy fix I’d rather skip the hassle of a service appointment.

Thanks for in help!

 

Same problem here, but I have a 2006. Just installed new tow light kit wiring and all. All grounds secure, tested the pin connect and boom, no power. Brake and turn signals work. No running lights.

Any help is much appreciated. Thank you

 

I have a 2010 and a 2017 tundra. The boat trailer-Running lights.... not working on either truck. All the other signals are functioning properly.

If I put the same boat trailer on my wife’s suv.... the running lights work just fine, so the trailers good.

Is this a common tundra problem...?

 

I still haven’t figured mine out, said F it and swapped my running light pin to the 12v constant pin, so they are always on now. Any light shed on the subject would be nice, it’s not a fuse, at least from what I can tell.

 

Bad trailer ground..

Figured out the issue to both of my tundras- trailer running light problem. There ended up being a bad ground on trailer, it popped the 30 amp tow fuse in both trucks. Apparently when I hooked it to my wife's suv yesterday to test it out, the trailer lights just happen to work fine because the trailer didn't have a chance to pop her suv fuse yet.... So this morning grounded the trailer wire, to the trailer, real good....changed the 30 amp fuses in the tundras... boom issue solved... running lights good both tundras..

 

I have same issue but my 30 amp tow fuse is not blown. Any suggestions?

 

I have a 2013 TRD Rock Warrior in Australia, yes it was converted from L to R hand drive in Vietnam of all places. Not a bad job all in all, the vehicle had only 12000 miles on when I purchased. Anyhow I have wondered ever since I first plugged in my boat trailer, why the running lights (tail lights) are always On, all the time as soon as the plug is inserted. All the flashers and brake lights function ok. Fuses and relays all good.
Looking at these threads, it looks as if the running Lts or clearance lights are not powered via the correct wire being No.7 Brown wire in the 7pin flat connector. So not activated via the park or headlamps switch/relay.
Also when brake lights are applied the Red 6 socket is powered (correct) but also powers the Yellow 1 socket and green 4 socket - which are flashers ??
Anyone have any ideas on this

 

I have the same issue. No fuse blown. 06 tundra sr5. Anyone figure this out? Looks like a know problem.

 

Same issue here on my 2010 Tundra. No power to the 7 pin for the running lights. Worked fine for years then bam, no power. All other lights, fuses and relays are good. I ended up adding a ground to the relay. The running lights work now but are always on when I hook up the trailer. Not ideal but it works. Anyone have a better solution?

 

I have a 2015 tundra but having opposite problem all market lights work but no turn signals or brake lights?

 

Ahh another day another (i dont even know how many) dollar saved from this forum. Hooked my boat up to bring it in to be winterized for the season, and blinkers and brake lights were working but no running lights on trailer were working. Here I was about to buy another whole set of trailer lights and spend another Saturday rewiring everything. Sure enough, quick google search later, check the forum and test light to the truck and easy enough found that my 30amp trailer light fuse was blown in my truck. Quick swap with the spare fuse and everything works perfect. Thanks all for the headache and money saved!!

 

Resurrecting an old thread, same issue (sort of). I have a 2016 Tundra SR5 with a similar issue. I have gone through the above thread suggestions and here is where I am. I have confirmed all the 30A fuses (#6-TOW TAIL, #11-TOW BRAKE, and #14-TOWING) are not blown and working. The flat four connector on the vehicle works correctly (using a magnetic set of lights to get by) but the round 7 does not function at all. After some guess work I a chance and connected my test light to the ground pin on the flat four and tested the light connections on the round 7. All lights function correctly. Has anyone else had this issue, and if so, what was your solution?

Thanks in advance,

Bob

 

I know this is an old thread but I found it trying to get my trailer lights to work, and thought I would post my solution.

I have a 2005 tundra sr5, trailer brake lights and turn signals worked fine, but running lights didn’t come on. After messing around with it, I realized the 7 pin to 4 pin adaptor had to be just in the right position in the 7 pin female connector to make good connection, then the lights would come on. I ended up spraying out the 7 pin connector on the truck with electronic spray cleaner and then putting di-electric grease on the 7 pin adapter to help take up more space on the plug. Trailer lights work fine now. I will go ahead and replace the 7 pin connector on the truck with a 7 pin/4 pin connector once I get the time, for a permanent fix.
Hope this helps someone else.