Trailer lights don't work

[Mike S.]

I just bought an older Nitro the other day, and none of the trailer lights work.  I bought a new light kit, and still nothing.  The trailer has a swing away tongue, but the pin hasn't been out in forever.  The ground is behind where the tongue swings, or at least where it's supposed to swing.  There is a ground wire, or so it appears to be, that runs from the swing hinge up to the tongue.  Do I need to have a ground to both parts of the swing away?  I energized the wiring harness last night with a battery charger, and got power all the way to the back of the trailer, but the old lights were junk, and full of water.  Today I can't get any power to the back.  I grounded my test light to the exact same spot, and nothing.  Please help.

[djkimmel]

Are you testing with the trailer hitched to your vehicle? With some trailers, I've always thought the ground goes through the hitch to the ball on the tow vehicle also, not just through the wiring. If this is a duh question, just ignore me, but it is often the simple things. Being a computer nerd, I always start with the simple things and work my way up.

There has to be a breach somewhere obviously. I have several ground wires going to the trailer on my Ranger Trail.

[Cy]

Mike,

Keep in mind that you are dealing with a car, so all ground wires must eventually make it back to the battery.  I would clean all the ground connections on the trailer and check any grounds that are near the hitch on the truck.  Also keep in mind that sometimes the lights will ground through the trailer not through the wires.  You can also use your test light to find good grounds, by hooking it to a power source and grounding it.

Cy

[thedude]

if the hitch receiver itself isn't grounded (from the ball to the tongue of the trailer) you will have lighting issues. make sure the hitch receiver, pin, pin-holes and ball are clear of surface rust. I used to be able to turn my hitch pin and make the lights go on and off on my old truck. Also check any fuses both under the dash and hood (relays) - if the original lights were shorted out you might have blown a fuse before you installed the new ones.