Lights issue

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Jey

Well-known member
Joined
Mar 16, 2019
Posts
146
Hello all,

I?m having an issue with my trailer lights. At first I could not get the running lights to turn on when plugged into the truck but the brake lights worked. Now nothing is working.

I jumped the 12v to the tail lights on the 7pin on the trailer and the running lights all came on including the tail light. I jumped the brake lights and nothing.

I thought my truck was the culprit for the lack of running lights at least but I tested my 7 pin on my truck and I have power at all pins.



I?m trying to fix one problem at a time as clearly I?m not getting signal to my brake lights but I wanted to tackle why I?m not getting running lights when plugged into my truck only when I jump the 7 pin on the trailer. I don?t know a lot about this stuff as it is but I?m hoping someone can shed some light on this
 

grashley

Well-known member
Joined
May 7, 2015
Posts
6,591
Location
Western Kentucky
To make sure I read this correctly:
When jumped from the 7 pin trailer plug, running and tail lights work.  Brake / turn signal do not.
At the truck 7 pin, you have power everywhere you should.

My comments:  The brake / turn signal use the same lights on most trailers, but are separate, left and right.
1.  Check GROUND pin on both plugs.
2. Check the bulbs.  One blown element each side could cause this.
3.  The trailer pigtail will run to a junction box.  Check this box to see if a wire (s) is disconnected in here.  Also check for 12V here from the truck to each light circuit - Left turn/brake;  Right turn / brake;  Running / clearance lights.  Check power, ground and brake as well.

This should narrow down where the problem is: in the pigtail or in the trailer AFTER the pigtail.  Since the truck shows power everywhere it should, I doubt it is the issue.

Thanks for posting one issue at a time!!!!!

It will help my poor memory if you would add your trailer and TV info to your signature.  Click on <Profile> near the top of the page.
 

Jey

Well-known member
Joined
Mar 16, 2019
Posts
146
Thank you grashley for your help. It was greatly appreciated!

Now I must admit my shame.


I spent $30 on fuses, I spent an hour making better ground connections in the clearance lights yesterday, so tried various scenarios and endless google searches.. and I still had no lights.

I eventually swapped out my onboard battery on the trailer and I was able to jump the pins on the 7pin and get the lights to work. However they still would not work plugged into my vehicle


Today my dad came over and I explained that I?m still having issues. He looked at my 7pin and said ?it doesn?t look like it fits? and I tell him I put it all the way in the 7pin on the truck and that?s as far as it will go. So he proceeds to shave down the raised part of the 7pin socket (the piece on top that lets you know which way to plug it in) followed by putting wd-40 on the outside of the plug and then he proceeded to push the 7 pin in with all his strength until it popped into the 7pin on my truck more than it had previously


And a miracle happened.. we had lights.


So.. I have no idea why the 7 pin does not fit in my truck. But I?m really glad that was the only issue we had. I will be ordering a new end to put on the trailer and hopefully it?s a better fit. Because I wasn?t able to get that thing back out of my truck on my own so I really don?t want to mess around with that one.
 

Jey

Well-known member
Joined
Mar 16, 2019
Posts
146
Rene T said:
Thank God for Dad's.

Yes!

I was really getting concerned about the lights not working. I kept thinking that somehow during the rebuild of the floor that we messed something up or cut wires or something.
 

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