Hey guys,  I hope all is well.   I have got my hitch put on with full electrical work on the vehicle.  I had to rewire the entire trailer.  I replaced everything but the tail lights them selves.  The lights worked last year but had some problems.  I followed the diagram for wiring a four flat.  I connected every color and grouned to the hitch since the rig is off the trailer.  It still won't work.  I know it''s getting the signal from the vehicle b/c it has test lights on the female connecter.

I split the brown to both lights.  I also used butt connecters for better conductivity and protection.  I was told if I ground it to the car it will be fine for a ground till on the trailer is that true?  How can I test these lights to see if they work?  There is no white for the lights them selves.  Should there be?  the ground is only coming from the car.  

Typical four flat connectors for trailers have a shorter white wire that needs to be ground onto the trailer.  The lights themselves are normally grounded internally via the screw mounts that attach the light to the trailer. You cannot trust that the hitch/ball connection is going to ground the trailer. If there isn't some sort of connector on that wire to begin with, I add a ring type, drill a hole in the trailer up by the coupler, sand the surface to bare metal and screw it down. That should fix your problem.

I'm not sure if I know what a ring connecter is.  If I drill a hole and put a bolt threw with the ground connected by a round connecter will that be ok?

Ring connector.

Yes, strip white wire, insert into ring connector, crimp with a pair of pliers.  Drill hole in trailer up by hitch coupler,  insert screw through ring connector and hole in trailer.  Tighten down.  

  I connected every color and grouned to the hitch since the rig is off the trailer. It still won't work.

You now have to actually ground the trailer to the tow veh.  Try the lights again with the hitch connected to the truck.

ok thanx guys I will try to hook it up in the morning.

Run a separate ground wire 14 gauge should be fine  connect all lights to this ground wire this way you will have redundant grounds the wire and the trailer ball .You should be able to just plug in the connector with out hooking up the hatch ball and if done right the lights should work.

Run a separate ground wire 14 gauge should be fine connect all lights to this ground wire this way you will have redundant grounds the wire and the trailer ball .You should be able to just plug in the connector with out hooking up the hatch ball and if done right the lights should work.

This is what the guy at the marine store told me to do, but it didn't work. So I ran a ground wire from the trailer side plug to the trailer and then ran a ground from the lights to the trailer. Works perfectly now.

Ok So I bought new tail light b/c the last ones I though may have been bad b/c of the rust and corrotion.  These have ground leads coming out of them.  The old ones hade no ground leads.  I guess the studs were the grounds.  

So you guys are saying that I can ground these to the ground I have coming from my car?  I have that ground tied to my trailer.  Can I run the leads from the lights up to were my other ground is?  Will this be fine.  Does the fact that the trailer is rusted a little interupt the ground threw the trailer?

The guy at the marine store told me to run them that way but it didn't work. I ran a ground from the lights to the trailer and then ran a ground from the trailer side connector to the trailer. Originally I ran a wire from each light to the ground on the trailer side connector but, the brake lights wouldn't work when the head lights were on, so I ran the ground from the lights to the trailer and it works perfectly now.

From the connector on the tow vehicle - make sure you have a good ground.  Use a test light to confirm.  On the trailer plug you should have a corresponding pin to match the tow vehicle plug.  That will be your ground wire.  Drill a hole in the frame of your trailer.  You can either drill and tap or use a bolt and a nut.  Be sure to scrape all paint and rust around that hole down to bare metal (about a half inch circumfrance should be fine).  Install a ring connector (pictured above) to this wire.  Now from this point run a separate wire (14 ga. should be fine) down each side of your trailer to the tail lights.  This will make a total of 3 wires with ring connectors.  (One running down the right, one running down the left and a ground wire from the trailer connector plug)  Take all 3 ring connectors and insert your bolt into the hole you just drilled.  If using a bolt and nut I suggest using an elastic stop nut which can be purchased at The Home Depot or any hardware store.  That will prevent the nut from loosening up and causing a poor ground situation.  Now take the ground wire off each of your lights and connect them to the new wire you just ran.  (Do not use wire nuts!  Either solder wires or use male and female stake-on connectors.  I highly recommend soldering the wires.)  Next push trailer up to tow vehicle.  Do not connect hitch ball.  Just plug your connector into the tow vehicle and your lights should work - if it was wired properly.  Good luck!

Ok bro thanx a million.  I am going to do esactly what you said.  So if I increase the lenth of a ground it won't afftect it any?   As soon as the snow melts AGAIN i will get back to work.  It snowed like hell today and last night here.

That is correct.  It will not affect anything.  Just make sure your connections are tight.  Dude, I live in Jackson, NJ, so I know about the snow.  We got about a foot.  Anyway, if you follow my instructions you shouldn't have a problem.  If need be, I am probably about 2 hours away from you - if you want to take the ride we can figure something out.  Good luck!

Mike (tennwalkinghorse)

O really bro are you up in Wayne the ramapo region?  I love lake ramapo.  They are suppost to be putting a launch in there.  Do you know about that.  

I have some more confidence now.  But I did before too but it didn't work.  I also have some help from my boss at work. He builds Harley and I am going to take it there.  I plan on printing your post so we can follow it.  

So do you ever fish this way?

hey guys i wanted to let you know today i got the tail lights working. thanx

So what was wrong?  Glad there working

I had the loom grounded to the trailer but not the vehicle.  The guy who done it put in a slave loom like a car would be.