Trailer lighting/wiring

lockedup5

lockedup5

overcompensating underachiever
Joined
Jan 30, 2008
Location
Burke County (Hildebran)
Park lights work, turn signals work, and brake lights work. But when the park lights are on and mash the brake all lights go out WTH?
Also when I have brakes pushed I can clip my test light on the trailer and probe my truck the light lights up WTH?
I am going to be replacing the lights any how but hoping its just a ground on one of them.

Any advice? I'm usually pretty good at this stuff but its got me stumped
 
My first guess would be a wiring issue. Probably a bad ground. It can carry enough current to run a light or three, but once the load gets high enough, the bad connection heats up and opens. I'd start with running a jumper cable from the truck frame to the trailer, see if anything changes.

Do you know if they worked previously?
 
I did the jumper cable thing and it didn't change. They said they did work before but that's been years.
I'm thinking it's probably in the rusty light fixtures them self. I will change them out and post up if any change
 
Is there a common ground connecting the lights to the frame or to the harness? What I mean is do the lights ground to the chassis, and then there's a ground wire at the pigtail, or is there a ground wire that runs from the pigtail to each light?
 
White = ground.
Trailer side white should be screwed into some nice scraped off bare metal on the trailer chassis by coupler...
 
I would disconnect trailer from truck and with a battery or battery charger energize the trailer wiring harness. If the lights don't work properly go to the individual lights with power source and connect. Repair bulb, socket, or ground till light works. Go back to front of trailer and repair wiring harness if needed. If the lights do not work when connected to truck you have a problem with truck and or trailer connector
 
It should also be grounded through the connector. Often, the ball gets covered in grease and corrosion and doesn't provide a reliable path to the battery ground. I've watched lights flash off and on as a trailer bounces down the road. Relying on the ball to ground it, especially if you're running trailer brakes, just isn't enough.
 
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