trailor turn and brake lights not working

bada_bing

Cadet
Joined
Aug 29, 2010
Messages
17
I am having some issues with my trailer lights not working correctly. I replaced mostly all my lights on the trailer because some of them were old and some that did not work. The issue im still having is that the rear lights are suppose to be break/turn/parking lights but the turn signals and the break lights don't work but rather only the parking lights. If memory recalls me correctly I believe there is a total of 4 wires including the ground.

Can someone assist me with some troubleshooting steps to check? Is there a wiring diagram that anyone can post to what wires do what coming from my vehicle.. I drive a ford flex...
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: trailor turn and break lights not working

Re: trailor turn and break lights not working

There is no difference between the break (actually it is "brake" or "stop" light) and turn signals. They are one and the same. Brown wire feeds the tail, marker and license plate light. Yellow and green feed the turn/stop lights. White is ground. All light assemblies must be physically grounded to the frame of the trailer which usually happens with the mounting bolts. If your tow vehicle has separate turn and stop lamps you will need a converter to run a four wire system. For example, some vehicles use separate bulbs for turn and stop whereas the trailer does not (stop and turn are the same bulb). When trying to make trailer lights work, ALWAYS ensure the plug on the truck is working otherwise you beat yourself to death trying to find a non-existant problem.
 

NetDoc

Chief Petty Officer
Joined
Aug 20, 2011
Messages
517
Re: trailor turn and break lights not working

Re: trailor turn and break lights not working

Atwood makes an inline light tester to help figure this out:

416-KtnwmiL._SL500_AA300_.jpg
 

burp

Petty Officer 1st Class
Joined
Aug 3, 2002
Messages
363
Re: trailor turn and break lights not working

Re: trailor turn and break lights not working

Hey, I've seen that before..... when I rewired my BIL utility trailer...........If you mistakenly swapped around the wires on the tail lights fixtures, the stop and turn lights will be hard to see with the lights off and impossible to see with the trailer lights on. The light bulb is a dual element bulb, the shorter element produces a brighter light than the longer element. The shorter of the 2 elements is for the stop/turn light. The longer bulb element is for the lights. Make sure the brown wire (trailer lights) is powering the longer element in the stop/turn/tail light bulb.
 

spdracr39

Lieutenant Junior Grade
Joined
Aug 30, 2010
Messages
1,238
Re: trailor turn and break lights not working

Re: trailor turn and break lights not working

And make sure you have a good ground. The higher amp draw of the brake lights will cause them all to go out under a bad ground situation.
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Re: trailor turn and break lights not working

Re: trailor turn and break lights not working

Just a thought. Do you have a tilt trailer? On mine I had to tie the ground from the tongue over the tilt to the main frame. Flaky as all get out before and now solid lights. Just passing ideas.
 

FLATHEAD MAC

Petty Officer 2nd Class
Joined
May 11, 2009
Messages
116
Re: trailor turn and break lights not working

Re: trailor turn and break lights not working

replaced wre harness on tilt trailer, ran all 4 wires of harness in split loom . thru front tubing, then where it pivots i split off for left side and right side alowing a little sag in harness to alow for tilting if needed. the white ground wire i kept to run full length otf trailer and ran down left side and terminated with ring conector to left light mount bolt[002.jpg

note the un terminated yellow ground wire is frm previous owner prior to repairs being made . all grounds have been cleaned/
 

Bridar

Petty Officer 2nd Class
Joined
Aug 28, 2011
Messages
110
Re: trailor turn and break lights not working

Re: trailor turn and break lights not working

After you check each fixture's white ground wire to ensure they have a good connection to the frame, also test your tow vehicle's socket to make sure the ground terminal is actually grounded. You can use a test light between the ground terminal and a turn (or park light) terminal. If the socket ground is not grounded, your lights will work intermitantly as they will be relying on the (unreliable) ground connection between the ball and hitch.
 
Top