trailer lights giving me a headache

[Kevin Davis]

ok so i hooked up the trailer the other day and i had no running lights on one side of the trailer, the blinkers and the stop lights were working just fine. so i thought i had a bad bulb or something so i replaced it with a spare new one i had.

turn the things on and again no running lights but this time on both sides, everything else still working. I figured I had a short somewhere so I start tracing everything down and find absolutly nothing.

I figure it was time to change out all the old wireing and completly go thru everything any way so I do. about five hours later after shrink wraping any connections and fishing the wires thru all the hiding spots. I finished and hook the thing up and POP blows the fuse, and once again no running lights but everything else works fine.

I now figure I have no clue what I am doing, the only thing left that is not new is the recieving plug on the back of my truck. So Im on my knees asking for any ideas you guys might have before I wind up replacing the trailer and truck out of stupidity.

btw this is a four wire setup, which is pretty standard.

thanks.

[HPBB]

sounds like a short somewhere. If you have cahnged the trailer then the truck is next. make sure your ground is hooked up. bit sounds like something on your truck might be shorted.

[Jig Man]

Clean all of your contacts real well.  It sounds like a grounding issue to me.

[xboxfisherman]

I had almost the same problem. Mine ended up being the connector on the truck was bad. Corrosion and what not from the winter.

[71Rig]

Had the same problem but in opposite, my side markers worked but nothing else did, it was the ground to the trailer frame that was bad.  However there is a little trailer tool that is a must have for this.  You need to get a $4.00 trailer test light for the truck end of the connection.  It looks like the trailer end but has 3 LEDs on it that will indicate what is and is not working on the truck.  Lot less trouble then pulling it all apart.

http://www.amazon.com/dp/B0009PS9UO?smid=A18S2VA36NY5VY&tag=nextag-sports-mp-20&linkCode=asn

You can get one at Wally Word or auto parts stores and the like.  While you are out get some dielectric grease.  You can use the same stuff you use on spark plug wires and it will protect against corrosion.  I keep a tube in the glove box.

[burleytog]

The solution is obvious.  Buy a new truck and boat.

[Al Wolbach]

  Quote

Had the same problem but in opposite, my side markers worked but nothing else did, it was the ground to the trailer frame that was bad. However there is a little trailer tool that is a must have for this. You need to get a $4.00 trailer test light for the truck end of the connection. It looks like the trailer end but has 3 LEDs on it that will indicate what is and is not working on the truck. Lot less trouble then pulling it all apart.

http://www.amazon.com/dp/B0009PS9UO?smid=A18S2VA36NY5VY&tag=nextag-sports-mp-20&linkCode=asn

You can get one at Wally Word or auto parts stores and the like. While you are out get some dielectric grease. You can use the same stuff you use on spark plug wires and it will protect against corrosion. I keep a tube in the glove box.

Good advice. Also use this grease on your boats running lights to prevent corrosion.

Your origional problem sounds like a ground problem. However a poor ground normally will not blow a fuse, just makes your lights act weird or not at all. The first step you need to take is to isolate the problem to the vehicle or the trailor by using the tool mentioned above or hook up another trailor to your vehicle(or another vehicle to your trailor). After you have identifed the problem to the vehicle or trailor then troubleshoot............Al

[Kevin Davis]

thanks guys, Im going to try some of these today and ill let you know what i came up with.

[BassChump]

If it's blowing a fuse only when the trailer is plugged in, then it's the hotwire to the running lights. It's grounding on the frame of the boat someplace or in the plug itself.

If it was in the truck, it would blow the fuse with or without the trailer hooked up.

          Hope this helps.

[Splat]

Open up your trailer plug on the truck. I'm assuming you have like a 7 way or so. Pull the inside (two screws one that crimps the wires and one that holds the contacts in place) and pull it out wires and all. Lots of times the spring breaks on the door and allows water inside. you can get a build up of rust and corrosion in the back of the plug that can cause shorting out.

Your original problem because you only had half your lights sounds like a trailer problem, the current problem could go either way. Basschump brings up a very good point about the truck always blowing the fuse, however the receiver could still have some gunk in it that makes contact when you insert the trailer plug.

Bill

[Kevin Davis]

ok, tried to replace the plug on the truck, and still haveing the same problem. im with you about it being a trailer thing, i will start with pulling each running light until i find the problem, hopefully it dont rain tomorrrow so i can work on it again. I will disconnect all four side running lights first and do one at a time until i find the problem.

[BassChump]

All the running lights are hooked up to the same hotwire that goes all the way back to the taillights. It is beginning to sound like the hotwire going to one of the running lights is grounding out. What I would do if I were you would be to take off each running light assembly and check the wires going into each one. On most running light assemblies a small steel plate is in there that the bulb assembly is attached to. Many times the wire connecting to that steel plate has rubbed on something over time and worn off the insulator. (the plastic that wraps around the wire).

It sounds like something very simple. It's just a matter of finding the one wire that's causing all the problems.

From what you have said so far, I'm betting its a grounded hotwire in one of those small side marker lights or the taillight. (probably one of those side marker lights)

Also I've had problems in the past with how those side marker lights are made. They are made very cheaply and I've had the hotwire ground to the frame with no visible clue. I tried replacing the entire side marker light and the problem went away. The marker light assembly is only a couple of bucks at Walmart or your local auto parts store.

         Keep us informed!!!!!!

[Kevin Davis]

changing out all the side marker lights today alone with the license plate light. that way i know it is all new and i hope this takes care of the problem.

I disconnected all the side markers and the tail lights worked so i know it is not a problem there but as soon as i plugged one side light in it blew the fuse, those things get expensive after several blow so im just replacing all the lights.

[BassChump]

Now we know it's the side markers so all you have to do is find either the bad side marker light or the hotwire going to it. Either the side marker light is bad or the wire. Can't be anything else at this point. Sometimes the bulb can be in a little crooked and ground out.

If it's working without the side markers, just work backwards (from the taillights towards the hitch) until you find the problem.

[Kevin Davis]

thanks guys, so far im replacing them all. i got two done tonight before it got dark on me, im even going to change out the license plate light so i know there are no bad lights at all. Ill let you know if that fixes the problem, it should since everything will be new even the wires.

[Kevin Davis]

hope the rain stops tomorrow so i can finish this and see if it works or if i need to pull the rest of my hair out.

[Kevin Davis]

Rain stopped and I finally got it figured out. Turns out the side marker lights have two female connections on them. One is ground the other hot. There is only one wire that runs to them and it is a hot wire. If you connect the hot wire to the wrong connection on the light, Poof, goes the fuse. Man do I feel stupid right now.

Anyway, got it figured out and atleast I have all new lights on the trailer now. I went with the Digital LED water proof lights all around along with all new wire from truck to trailer. I even changed out the truck plug with a LED plug.

An expierence I will never forget, so I guess I learned something from it after all. Thanks all for you input, it helped alot even if Im not the smartest fish in the pond.

[BassChump]

I'm glad you got it taken care of and there is no need to feel stupid. I'm a pretty fair mechanic and simple stuff tricks me all the time. It seems it's always the last place or last thing you check.

I just replaced one of my tail lamp assemblies on the back of my trailer because the old one cooked the light. It's one of those waterproof light assemblies that you can't unscrew so I thought you had to replace the entire assembly. As I was taking the old one off, I saw there is a plate on the bottom that you take out and all the bulbs are connected to that plate. I could have replaced just the bulb but I got lazy and didn't look.

Luckily the new assembly only cost 9 bucks at Wall-Mart so at least I didn't go broke.

Even the pro's don't catch stuff at times.

I had a problem with my boat late last year. The #1 cylinder was flooding out. I took it to 3 different "professional" mechanics. Not one of them figured out the problem.

A few days later I went to a place in the next town to buy some pre-mix oil. I happened to mention my problem to the guy at the counter. He walked back, grabbed a small rubber thing, told me to install it and it's worked great ever since. It was just a fuel pump diaphram and it ended up costing me $1.69 to fix it.

Nobody knows it all so don't feel bad.

[tennwalkinghorse]

It sounds like you had a bad ground to start with by rewiring you now created a short. First check to make sure the fuse is rated right. Now with no power use a multi - meter set on continuity to check for the short. Open each light lens and disconnect each light and or connection one at a time . Connect one test lead to ground and the other lead to the power wire feeding the light. If the meter beeps or you read ohms the problem is in the circuit. Make sure there are no strands of wire touching the frame you my have a bulb with the filament that is shorting to ground and not open. Finding a short is very time consuming just go one wire at a time. Lots of luck

PS: Never over rate the fuse you can cause a wire to over heat and burn. All so using dielectric grease on all your connections is a good idea it cuts down on corrosion.  Hope I was of some help to you.

Walking Horse