Texas Fishing Forum

Trailer Light Frustration

Posted By: I'm The Dude

Trailer Light Frustration - 10/29/18 08:25 PM

So this is a weird one I have never experienced. My trailer lights are all on all the way around as far as running lights go, but the left side blinker and brake light are the only ones working correctly and the right side brake/signal is not functioning.

What I have done so far...
1. I originally thought "ground", but have not found any bad grounds.
2. Then I checked the plug and plug receiver at the truck and front of trailer, one of the prongs on the 7 round was getting pushed down when being plugged into the back of the truck. Changed this and the truck 7 round receiver, thought this would fix it, but no, still the same problem.
3. I have checked the fuses in the truck and have only found one popped the trailer tow back up lamp #70 10A under the hood. Replaced it, but have not made it back to the storage to check if this is solved my issue, but I'm not sure how it could be my fix...

Truck: 2011 F-350 Diesel
Trailer: 2016 EZ-Loader for a Skeeter

Anyone else have this issue? HELP!

Thanks in advance.
Posted By: Cast

Re: Trailer Light Frustration - 10/29/18 09:12 PM

Bulb?
Posted By: I'm The Dude

Re: Trailer Light Frustration - 10/29/18 09:40 PM

Originally Posted By: Cast
Bulb?


The light works, but only the running light, no flasher or brake light. They are LED also, would that be possible with an LED? Would an LED go bad to where the running light still works and all the individual LEDs in the light worked the flasher and brake light function would work too...?

Update: the one bad fuse I replaced did not solve the problem.
Posted By: Tin Star Cajun

Re: Trailer Light Frustration - 10/29/18 09:51 PM

On my Champ trailer I had lights work for an hour then pop the truck fuse. Three days and about 8 hours of work finally my buddy pulls the license plate LED light and found that one wire was slightly pinched at the frame and after an hour it heated up enough to blow the fuse. Not saying that’s your problem; just saying it could be something out of the norm so check everything. Good luck
Posted By: ChuChu1

Re: Trailer Light Frustration - 10/29/18 10:40 PM

Originally Posted By: I'm The Dude
Originally Posted By: Cast
Bulb?


The light works, but only the running light, no flasher or brake light. They are LED also, would that be possible with an LED? Would an LED go bad to where the running light still works and all the individual LEDs in the light worked the flasher and brake light function would work too...?

Update: the one bad fuse I replaced did not solve the problem.


Running lights and brake lights are different circuits.
Posted By: Stump jumper

Re: Trailer Light Frustration - 10/30/18 01:47 AM

Originally Posted By: ChuChu1
Originally Posted By: I'm The Dude
Originally Posted By: Cast
Bulb?


The light works, but only the running light, no flasher or brake light. They are LED also, would that be possible with an LED? Would an LED go bad to where the running light still works and all the individual LEDs in the light worked the flasher and brake light function would work too...?

Update: the one bad fuse I replaced did not solve the problem.


Running lights and brake lights are different circuits.
yep, pull plug at light and test each wire with emergency flashers on. Green is right brake/blinker and yellow is left. Just a cheap tester light and good ground is all you need. Turn on headlights or parking lights since you know they are working to make sure you have good ground on tester.
Posted By: I'm The Dude

Re: Trailer Light Frustration - 10/30/18 07:03 PM

Originally Posted By: Stump jumper
Originally Posted By: ChuChu1
Originally Posted By: I'm The Dude
Originally Posted By: Cast
Bulb?


The light works, but only the running light, no flasher or brake light. They are LED also, would that be possible with an LED? Would an LED go bad to where the running light still works and all the individual LEDs in the light worked the flasher and brake light function would work too...?

Update: the one bad fuse I replaced did not solve the problem.


Running lights and brake lights are different circuits.
yep, pull plug at light and test each wire with emergency flashers on. Green is right brake/blinker and yellow is left. Just a cheap tester light and good ground is all you need. Turn on headlights or parking lights since you know they are working to make sure you have good ground on tester.


Good call at the light, have not tried that yet with my tester. So far I have found 2 of the 10 fuses in the truck bad, neither of which fixed the problem. Will test this evening after work and update.
Posted By: Stump jumper

Re: Trailer Light Frustration - 10/31/18 04:23 PM

I have a 4 wire flat to 7 wire round adapter that has indicator lights to tell you if you have a good connection at the truck. It is handy for my trailers that are 4 wire. My Tacomas were terrible about getting a good connection. I thought maybe my Tundra was carrying on the Toyota legacy for sucky trailer connectors but I think this time the fault is on the boat side. I need to find a 5 wire with the lights.
Posted By: Big_Country01

Re: Trailer Light Frustration - 11/01/18 02:21 PM

Do you have an actual ground to the frame of the trailer? Many of the trailer harnesses do not have an actual ground to the frame. On almost all of my trailers i have had to take the white wire on the trailer side, add an electrical connector and screw it into the frame. Never a single light problem after this is done.
Posted By: I'm The Dude

Re: Trailer Light Frustration - 11/06/18 04:47 PM

Originally Posted By: Big_Country01
Do you have an actual ground to the frame of the trailer? Many of the trailer harnesses do not have an actual ground to the frame. On almost all of my trailers i have had to take the white wire on the trailer side, add an electrical connector and screw it into the frame. Never a single light problem after this is done.


Yessir, there are a couple built into the lights that when the screw is run through it makes the ground connection. These are the only grounds.

Update: Still having the same issue, the 2 fuses replaced did not fix the issue. I have tested everything from the light to the tongue. Everything at the truck is functioning. I am completely confused. May start completely over and see if I missed something.
Posted By: spankyttx

Re: Trailer Light Frustration - 11/06/18 11:32 PM

just for grins, have you tried a ground wire from the trailer frame to the truck frame
Posted By: ChuChu1

Re: Trailer Light Frustration - 11/07/18 11:57 PM



https://www.youtube.com/watch?v=3H5_g2lyOcs

Use a MultiMeter to Troubleshoot Trailer Lights. Part 2

https://www.youtube.com/watch?v=1ixTasxKZSE
Posted By: dk2429

Re: Trailer Light Frustration - 11/11/18 12:37 AM

Check your yellow wire. It runs the brake/turn signal on the left side.
Posted By: Winger Ed.

Re: Trailer Light Frustration - 11/16/18 12:25 AM

I had a similar problem on my 2006 F-250.

After trying everything I knew to do, and talking to everyone but the Voo-Doo lady in West Dallas-

I found out of about 100 fuses on the truck,
there is a handful of fuses for the rear lights/trailer plug.
It was one of the little yellow ones in the box under the hood near the brake master cylinder.
Posted By: Tallgrass05

Re: Trailer Light Frustration - 11/16/18 02:44 AM

You said you checked the ground, but how did you actually check it?
Posted By: 04champ

Re: Trailer Light Frustration - 11/26/18 06:30 PM

Originally Posted by I'm The Dude
Originally Posted by Big_Country01
Do you have an actual ground to the frame of the trailer? Many of the trailer harnesses do not have an actual ground to the frame. On almost all of my trailers i have had to take the white wire on the trailer side, add an electrical connector and screw it into the frame. Never a single light problem after this is done.


Yessir, there are a couple built into the lights that when the screw is run through it makes the ground connection. These are the only grounds.

Update: Still having the same issue, the 2 fuses replaced did not fix the issue. I have tested everything from the light to the tongue. Everything at the truck is functioning. I am completely confused. May start completely over and see if I missed something.


That does not sound like a very good grounding scheme.

I have a wire spliced off the harness that attaches to a stud on the trailer frame up at the very front.

Resistance between your truck ground and trailer frame should be less than ~50-75ohms
Posted By: I'm The Dude

Re: Trailer Light Frustration - 11/27/18 05:05 PM

Update: Have been traveling a lot for work and have not had time to get to the boat storage to start over.

Tested the grounds with a test light. Then tested with a meter, I have found a wire schematic for the trailer from EZ-Loader and that confirms I missed a one that I could not find originally. I will update when I get back to the boat.
Posted By: I'm The Dude

Re: Trailer Light Frustration - 12/21/18 02:20 PM

Well, I figured out the problem and it was literally the worst case scenario. On the Ez-Loader trailer that Skeeter no longer puts their boats on is a 5-flat changeover that is actually 2 five flats into 1 (10 wires)... This is where my right turn signal was bad. Being me, I gutted the boat trailer of all wires and rewired the whole trailer with a new harness. Everything works now!
Posted By: ChuChu1

Re: Trailer Light Frustration - 12/21/18 04:43 PM

First time I have ever heard of the boat wiring affecting the trailer lights.
Posted By: I'm The Dude

Re: Trailer Light Frustration - 12/22/18 04:14 PM

Originally Posted by ChuChu1
First time I have ever heard of the boat wiring affecting the trailer lights.


Ah ha good catch. Fixed it for you captain.
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