trailer lights not working

daveski1964

Seaman Apprentice
Joined
Mar 20, 2014
Messages
39
my trailer lights only work when using turn signal. flashers or pushing ,brake lights....parking lights do not work when head lights on at nite .. ....is this a problem with truck wireing.......turn signals work ,,flashers work ..brake lights work ,,no maker light or parking lights,,,,,, cant pull at nite no lights ..
 

midcarolina

Chief Petty Officer
Joined
Jul 16, 2013
Messages
631
first take a 12 volt test light and check between the white wire and brown with the running lights of tow vehicle on, then if you have power there Check your white wire ground on trailer....... and if each light has a white pigtail make sure it is connected to clean metal...bad ground connections cause all kinds of funky things to happen.....
 

TD_Maker

Chief Petty Officer
Joined
Aug 31, 2005
Messages
564
Ground each light to the trailer frame...AFTER you scratched down a good surface for the ground wire. Do the same thing up front....make sure you scratch down a good surface for the white ground wire. These type of problems will drive you crazy, and most often a good grounding surface is to blame.
 

aburke120

Petty Officer 2nd Class
Joined
Jun 27, 2011
Messages
183
I had a gm pickup that had fuses under the hood for all trailer light functions maybe one is blown. the owners manual showed where they were as there was two fuse panels in different locations.
 

lckstckn2smknbrls

Lieutenant Junior Grade
Joined
Sep 18, 2008
Messages
1,114
Ground each light to the trailer frame...AFTER you scratched down a good surface for the ground wire. Do the same thing up front....make sure you scratch down a good surface for the white ground wire. These type of problems will drive you crazy, and most often a good grounding surface is to blame.
Run a white ground wire from the connector to each light by passing the trailer frame completely.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,588
Run a white ground wire from the connector to each light by passing the trailer frame completely.
On my trailer that would require me to run over 150' of extra wire. Making a good ground connection at each light is the best way.
 

lckstckn2smknbrls

Lieutenant Junior Grade
Joined
Sep 18, 2008
Messages
1,114
On my trailer that would require me to run over 150' of extra wire. Making a good ground connection at each light is the best way.
Run one wire from the connector to the mounting stud of the nearest light, then to the mounting stud of the next light, then to the mounting stud of the next light, then to the mounting stud of the next light and finely back to the connector making a loop around the whole trailer frame.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,588
Please tell me how that is better than just grounding at the frame. In that scenario, you have one bad connection and you lose all your lights downstream. With the ground at each light, you only lose one light if the ground goes bad.
 

lckstckn2smknbrls

Lieutenant Junior Grade
Joined
Sep 18, 2008
Messages
1,114
Please tell me how that is better than just grounding at the frame. In that scenario, you have one bad connection and you lose all your lights downstream. With the ground at each light, you only lose one light if the ground goes bad.
Actually you have ground wire going 2 directions so if the ground wire is broken it's still making contact and at ever mounting stud the ground is in contact with the frame.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,588
Actually you have ground wire going 2 directions so if the ground wire is broken it's still making contact and at ever mounting stud the ground is in contact with the frame.

So why not have this ground stud at every light and forget the wire?

With my trailer, I drill a hole, grind to bare metal around the hole, attach the ground wire lug to a screw and then paint the whole thing after it is all tightened up. I have never had a ground issue in over 30 years of boating using this method.
 

lckstckn2smknbrls

Lieutenant Junior Grade
Joined
Sep 18, 2008
Messages
1,114
The ground stud is already at every light it's the mounting stud that holds the light to the trailer frame and it's this ground that usually gives people all the trouble.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,588
The ground stud is already at every light it's the mounting stud that holds the light to the trailer frame and it's this ground that usually gives people all the trouble.
i agree, the lights that rely on their mounting studs for ground are a problem since you can't seal the connection on both sides. I don't use those types of lights for that very reason.
 
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