Trailer Light question - No brake lights!

SteelNuttz

Seaman
Joined
Apr 3, 2012
Messages
65
I bought a boat with a trailer, and the lights on the trailer were busted out when I bought it. I purchased a new set of lights for the trailer, and now that I have them installed - the brake lights won't work. The lights work when I turn the lights on in my van, the blinkers work...but when I hit the brakes, the lights go out...

The lights themselves do not have any ground wires coming out of them for my to attach to the trailer, the only gound wire I have is up near the hitch and it's attached directly to the trailer.

Anyone run into this before or have any suggestions to try out? Thanks.
 

royal0014

Master Chief Petty Officer
Joined
May 6, 2010
Messages
874
Re: Trailer Light question - No brake lights!

The mounting bolts are the ground. The metal they attach to (the trailer) must be bright and shiny, no paint or rust. Clean front and back of the mounting holes.


<<)))(((>>
 

2 Eagles

Petty Officer 1st Class
Joined
Apr 4, 2011
Messages
206
Re: Trailer Light question - No brake lights!

The bolts on the light are the ground. You may have to run a ground wire from the front of the trailer to the lights. My trailer was like that. Bought new lights & installed them and ran the new wire to the back of the trailer. When I pulled out the old the ground wire it was only attached to the hicht area. The trailer was old and had to much resistance for the new lights to work right.

^^ Posted as I was typing.

But he his correct.
 

SteelNuttz

Seaman
Joined
Apr 3, 2012
Messages
65
Re: Trailer Light question - No brake lights!

I think the lights are attached with a plastic bracket so I don't think the bolts are touching anything electrical in the lights...either way, I'll try to clean up the connections since my trailer is fairly rusty!
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Trailer Light question - No brake lights!

The trailer frame is the same as a separate ground wire. With the lights securely bolted to the frame that makes a ground conenction. However, if the lights are bolted to a bracket that is bolted to the frame that has the tongue bolted to the frame --- see where this is going? Every joint must make a solid electrical connection or you don't have a good ground. That is why some folks run a separate wire to the mounting bolt that serves as the ground for the light. Both of them don't so make sure you pick the right one.
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: Trailer Light question - No brake lights!

... the brake lights won't work. ... the blinkers work...but when I hit the brakes, the lights go out...

The "Blinkers" (Turn Signals) and the Brake lights are the same circuit on the trailer.
They are different circuits in the tow vehicle.
The "Lights" (Tail Lights) are a separate circuit.

Do you have a Towing light Converter in the tow vehicle to attach the trailer lights?

Turn on your Tail lights and the Emergency Four Way Flashers. What happens on the trailer?

What Year/Make/Model is the tow vehicle?
 

Slide

Petty Officer 1st Class
Joined
Aug 2, 2010
Messages
269
Re: Trailer Light question - No brake lights!

Check your fuses as well. I bought a brand new F-150 and was stumped as to why the running lights would work on my trailers but not the brake/turn signals - Ford gives you an extra fuse in the glovebox that you have to install yourself to activate the relays for the trailer wiring harness.
 

SteelNuttz

Seaman
Joined
Apr 3, 2012
Messages
65
Re: Trailer Light question - No brake lights!

Thanks for all of the info. I will get more info for you tonight - I don't have my vehicle with me but it's a 2010 Dodge grand caravan.
 
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