I am trying to fix the lights on a trailer I just recieved. its a really basic boat trailer, with stop, turn and tail lights on the back, the all in one kind. problem is, when I turn my lights on, the turn signals stop working, and the tail lights dont work at all. how could this be? it seems like a really easy setup, two wires come out of each light, and one main ground wire. so 5 in all. what do I need to do in order to get all the lights working?

 

ok, I am under a deadline, so if anyone has any ideas.

here is what I am figuring out.

each light has two wires. brown and red. from the truck, I have the typical brown green white and yellow. the brown is supposed to be the tail lights and stop lights, yellow is the left signal, green the right. white is the ground.

I have turn signals working. hazards work, brake lights, just no tail lights.

where should I look? is this a fuse issue? any advice would be awesome!

thanks!

 

Tail and stop can't be on the same circuit.

 

Ok, you have Tail, LT, RT, and ground. Both the LT & RT will also have the stop circuit.

 

Make sure the connector on your truck has power on the tail light wire. If it does I would check the bulbs in both lights, and then check the grounds on each light. Even though the turn signals work they still could have bad grounds, and they can do some screwy things with bad grounds. And as 06ram2500 stated the brake lights work off the turn signal wires not the tail light wire.

 

Wire both the tail lamps together and RT & LT to each lamp respectively

 

thats what it is now. both brown wires from both sides are together, and then both lights are connected to their respective wires. the catch is that even though I dont have tail lights, when I turn either my turn signals, or hazards on, and then my light switch to the "on" position...it kills my signals.

I am so confused. this should have been really easy.

I will check to make sure i have power at the tail light, whats the best way to do that?

 

yeah, I just read about that. I was confused

 

Use a circuit tester to check for tail light power. BTW, you don't want to use flashers to check for RT & LT signals/brakes.

 

rodger that.

I have been checking all independantly. I used a circuit tester at the truck and I have power at the tail light port. so its between the harness and the light. I checked the light bulb it looks fine. what kills me is I could get away with just using RT and LT, but if I have my lights on while driving down the highway, they are all shut off.

I am beating my head on a wall here, I dont know what else to check! I have about an hour and a half before I want to be on the road too!

 

ok, I have absolutely confirmed its not the truck. I hooked it up to another boat trailer, and everything works fine.

so I wonder if the lights I got are bad.

they shouldnt be, they are simple, stop turn and tail lights. they should work fine. the only thing is they dont have individual grounds on them.

 

Grounds through the frame/hitch. On one of the bolts is a ground wire. I bet the culprit is the plug. Is it one of those inline 4 jobbers?

 

yeah, it is an inline 4, but I thought that was the problem first, and replaced it with a new one. so that shouldnt be it.

no idea whats goin on here.....

 

Put some electrical grease, alot, on the ball. This happened to me once due to new paint on the underside of the hitch on the trailer, but rust I think will do the cause the same problem. HTH & keep us informed.

 

Try this. Just hook up the white (ground) wire and the brown (running lt/tail lt) and see if the lights come on with your headlights. If they come on the circuit is good. Then hook up one of the signal/brake wires and check for lights and that one signal. If the lights flash you have a ground problem on that side. If not, hook up the other wire and do the same test. That will isolate your problem to which bulb, socket, ground or wire is faulty.