Okay... my utility trailer has officially pissed me off...... I am having horrible problems with my trailer lights.... I have been through 2 wiring harnesses and 2 sets of taillights and both are doing the same thing.. well sort of....

1st set:

Headlights off:
turn signals work
brake lights work

Headlights on:
taillights work
turn signals work
brake lights dont work....
when I hit the brakes the whole taillight just turn off.....

2nd set:

Headlights off:
turn signals work
brake lights work

Headlights on:
taillights work
turn signals work
brake lights dont work....
when I hit the brakes the whole taillight just turn off.....


The same thing happens hooked to my blazer and my silverado.... my silverado is factory wired for a trailer... so it cant be the trucks right?? oh yeah... the second set of lights/wiring harness does nothing when hooked to my blazer.... it works as listed above when hooked to my pickup...... this is very very maddening.....

it is a 4-flat wiring harness and not only did I scrape the powdercoat off of the trailer for the ground, I used a self-tapping sheet metal screw......

PLEASE SOMEONE HELP ME!!!!!!!!!!!!!

 

wow almost sounds like the wires on the trailer r messed up and maybe switched around

 

Does this help?

[IMG]local://upfiles/2910/37B8488688B64956BE41FF72A41C5192.jpg[/IMG]

 

I've wired so many trailers its not even funny..lol thats why this makes me so mad.... I mean the wires are color coded... pretty hard to mess up......

the wires are all correct... the lights that work also light up dimly......... maybe the lights arent getting a good ground where they mount to the trailer????

i know that

brown-taillights
green-right turn/brake
yellow-left turn/brake
white-ground to trailer


if the wires weren't right then they wouldnt work at all..... this only happens hooked to my blazer... hooked to my pickup they all work correctly unless the headlights are turned on...
it isnt the trucks because I just hooked my boat trailer to both of them and those lights work properly..

the lights mount to L-brackets that bolt to the trailer frame, however, the bolt holes and trailer frame are powdercoated... could this cause the problem??? I mean, the lights technically ground to the frame through the bolts they mount with right?

 

Take a meter and test all the connections. Make sure that the wires don't have continuity to ground that shouldn't. Test voltage at the lights. Disconnect one light and test it all out, then test the other.

 

Yeah I think the lights do ground thru the bolts that they mount with, so try scraping some powdercoat off where the bolts mount up and then try it again. I know crappy/loose grounds can cause lights not to work.

 

FIXED IT!!! could not ge ta good ground anywhere except the trailer tounge... sooooo I ran a ground wire from the light mounting bolts through the frame rail and to a self tapping screw on the tounge.... works perfect now.. thanks for all the help guys!

 

good to hear u figured it out!

 

Glad thats solved for you. Its weird that you could only get a good ground at the tounge.