Odd trailer light issue

PowerAddict

Chief Petty Officer
Joined
Aug 8, 2007
Messages
418
My brake lights and turn signals work, but running lights do not, on either side, and I find that strange. Now, one thing I will say, My two yellow side lights, are not connected, but those are in parallel so that shouldn't matter right?

Any ideas?
 

Snowfish

Petty Officer 1st Class
Joined
Jul 3, 2009
Messages
234
Re: Odd trailer light issue

First we need to determine if you have juice to the vehicle trailer receptacle.

Most tow packages will have a separate fuse for the running lights, left turn, & right turn. Probably under the hood in the power distribution box.

No juice from the tow vehicle almost undoubtedly means a blown fuse.

Next question is why did it blow? 1) pure magic 2)short in trailer or vehicle receptacle.
 
Last edited:

woosterken

Lieutenant
Joined
May 18, 2005
Messages
1,431
Re: Odd trailer light issue

is it possible that just the marker filament in the bulbs are broken?

woosterken
 

Rocky_Road

Lieutenant Commander
Joined
Oct 8, 2008
Messages
1,798
Re: Odd trailer light issue

Get one of these...tells you with LED lights if your towing vehicle, or your trailer, is the problem!

http://www.jcwhitney.com/4-POLE-CON...RS/GP_2004471_N_111+10201+600016436_10101.jcw

wh4zr.jpg
 

Utahboatnut

Senior Chief Petty Officer
Joined
Jan 15, 2009
Messages
785
Re: Odd trailer light issue

Not too strange since the running lights are their own circuit and use a different fillament in the bulb. If you have a test light test the vehicle plug if it is okay the start working back to the trailer lights. If they are the plug in type then you can unplug and test the plug which will tell you if the bulbs are bad. On sealed lights you cant take them apart to check the bulbs so you have to use a battery and test leads. Make sure the marker lights arent wired wrong and putting the hot to the running lights to ground. They should be spliced to the running light wire and have their own ground. If the signals and brake lights work fine then it probably isn't the main ground which is usually the problem with lights.
 

Shizzy

Ensign
Joined
Aug 5, 2007
Messages
984
Re: Odd trailer light issue

First we need to determine if you have juice to the vehicle trailer receptacle.

Most tow packages will have a separate fuse for the running lights, left turn, & right turn. Probably under the hood in the power distribution box.

No juice from the tow vehicle almost undoubtedly means a blown fuse.

Next question is why did it blow? 1) pure magic 2)short in trailer or vehicle receptacle.

that was the problem I had with my Ford Ranger. there was a seperate fuse under the hood. I have never had an issue since. Im assuming the P.O. hooked up to a badly wired trailer.
 

PowerAddict

Chief Petty Officer
Joined
Aug 8, 2007
Messages
418
Re: Odd trailer light issue

well, I shoulda done this in an order so I know what exactly was wrong. But I put the side marker light on, and re-wired a wire that i thought looked too loose AND plugged it into a different vehicle and they all work brightly now!

Thanks for all the help!
 
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