Trailer Electronics/Break Lights

[love2fishhave2work]

Hello, I just picked up my boat/trailer from storage and connected the 5 way trailer wire connector to the vehicle adaptor prior to towing. Tested the lights and noticed that all lights, night lights, left turn, right turn, hazards work but the break lights do not. Does this mean my trailer breaks are also not working and how can I isolate the cause? Is it a problem with the vehicle receiver or the trailer wire? Any suggestions on what could be the issue, how to identify it and how to fix it would be great.

 

Thanks you in advance.

[John Bacon]

Just to be clear, are you saying that the break lights on your vehicle don't work? Or, the break lights on the trailer don't work?

 

In a four wire harness the break lights run off the same wires as your turn signals. If you have turn signals on the trailer than I don't think the trailer is the issue if you are not getting break lights.

[BillM]

If the turn signals are working but the brake lights aren't, it's probably the bulbs, not the wiring.

[Garnet]

Also the ball to trailer receiver is a big part of your ground.

 

I don't worry about to much until I tow a little bit make a few turns sorta knock the rust off.

[Terry]

there is a lot of lights working to be a ground problem, so

I would check the connector to see if you are getting power when brakes are applied

[love2fishhave2work]

Thanks, it is the break lights on the boat and not the car. How can one check the connector to see if the power is coming? The bulb makes sense but I would be surprised if both would burn out at the same time. What is the easiest way to figure out if power is coming in from the vehicle into the connector to make sure the issue is on the trailer and not on the car?

[Terry]

pop out one of the light bulbs and get a piece of wire hook it to the yellow and to the bottom of the light then the side of the light to the white wire and have some one push the brakes

[John Bacon]

Thanks, it is the break lights on the boat and not the car. How can one check the connector to see if the power is coming? The bulb makes sense but I would be surprised if both would burn out at the same time. What is the easiest way to figure out if power is coming in from the vehicle into the connector to make sure the issue is on the trailer and not on the car?

 

Princess auto sells testers. The flat four tester is $3.99; I didn't notice if they had a 5 wire tester.

 

If you had a VOA meter you should be able to read voltage on the vehicle and continuity on the trailer.

Edited May 20, 2013 by JohnBacon

[davey buoy]

Princess auto sells testers. The flat four tester is $3.99

That'll take away most of the guess work.

[Fisherman]

If you have a 12 volt battery of any size, take 2 wires, battery negative to the ground side of the trailer plug, (it's the one that has the cover around it). Take the other wire from the battery positive and insert it into each one of the the other holes, you'll find out what light's up and what doesn't and if any bulbs are pooched. As for useing the trailer ball/coupler are your ground, only lazy people do that. Run a dedicated ground from each light socket to a central spot and up to the white trailer connector. The biggest annoyance is some turnip going down the road with lights blinking cause they don't have a proper ground. Ya don't know if they're going to stop, turn left/right or attempting lift off.

[love2fishhave2work]

I am completely baffled by this issue. I purchased the flat four tester and it appears to work just fine. running lights light up, LT and RT both work and when I press the breaks both LT and RT light up so it appears power is coming out of the vehicle. I just got off the phone with EZ Loader to order new lights and they tell me that it is not the light. According to them, the lights I have are all one unit. If the LT and RT lights work then the break light is not burnt out as it is the exact same light. Hence it is not the light.

 

I am not sure what to do now. I guess I will find someone with a pull vehicle to hook up my trailer to see if they have the same issue. If not then it will be the vehicle and if yes it will be the trailer. How to correct it baffles me. If anyone lives in the Rutherford and Bathurst area and has a pull vehicle, I would love to swing by or vice versa to attach my trailer to your vehicle.

[BillM]

So it's not a dual filament bulb? Wouldn't that be funny

[Roy]

I don't know but it seems to me that 15 minutes at a trailer shop would fix your problem.

[love2fishhave2work]

hocked up to a friend truck and everything worked. must be a short circuit in the truck that is causing it. appreciate the help.

[gburdzin]

I am completely baffled by this issue. I purchased the flat four tester and it appears to work just fine. running lights light up, LT and RT both work and when I press the breaks both LT and RT light up so it appears power is coming out of the vehicle. I just got off the phone with EZ Loader to order new lights and they tell me that it is not the light. According to them, the lights I have are all one unit. If the LT and RT lights work then the break light is not burnt out as it is the exact same light. Hence it is not the light.

 

I am not sure what to do now. I guess I will find someone with a pull vehicle to hook up my trailer to see if they have the same issue. If not then it will be the vehicle and if yes it will be the trailer. How to correct it baffles me. If anyone lives in the Rutherford and Bathurst area and has a pull vehicle, I would love to swing by or vice versa to attach my trailer to your vehicle.

 

If the LT and RT lights work individually then the brake lights should work as well. Are you sure that there is no light output at all (even very dim) when you press the brakes? Maybe check when it's dark in order to see better. If there is a dim light, then you have a poor ground which can not carry enough current for both lights to work well simulaneously.

[gburdzin]

Oh...glad you got it isolated. Nevermind my previous post.

[vance]

I know on my gmc with the factory wiring for a trailer,the lites for the trailer have a separate fuses.so that if the trailer shorts out you still have vehicle lites.I borrowed a trailer and it blew both the signal and brake lite fuses which left me scratching my head until I asked a mechanic who knew about such things.

 

vance

[porkpie]

Likely a fuse, Had the same problem! You driving an F150 by chance?

Edited May 22, 2013 by porkpie

[bare foot wader]

@ porkpie - interested why you asked if it's a ford, sometype of known issue?

 

my last ranger kept blowing 2 fuses for my trailer lights, a fuse under the hood and one in the panel by the glove box. took me forever to figure it out, without the fuse diagram i had to go through and inspect each fuse one by one until i found the burnt ones

 

it was a 7.5 amp fuse that i had to replace every couple months, then I replaced it with a 10 amp fuse and never blew again

[porkpie]

Myself and a few buddies drive f150's and a couple of us have had fuse issues when towing. Minor but annoying.

They are all late model, I don't know if its a known issue, but it is for us.... LOL!