Please help me before I loose my freaking mind. I worked on this for no shorter then 6 hrs. Still giving me issues. I have no running lights on the trailer. It keeps popping the fuse under the hood. I installed new 7 pin connectors(male and female. Traced the wires back. Checked the truck plug for power and ground, checked for continuity in the trailer whip wires, got underneath and found a melted mess where the trailer whip connects to everything else. Cut all that out and started fresh. I am at a total loss. I have trailer brake lights and turnsignals but every time I turn the running lights on the fuse pops. I have looked for bare wires, etc. The only strange things I have found is that with a test light on the truck side the turn signals will light up when probed with positive and negative.

Any wiring experts here . It's a MSI cargo trailer.

Please help I am pissed off an lost. Not a good place to be

 

So, I think the markers are fed by the green lead. If you disconnect the lead for the markers at the J box, you can plug in and turn on the markers and the fuse doesn't blow, correct? If it blows the fuse, your trouble is ahead of the J box.

If the fuse holds, can you tell how the feed runs for the markers? If you can, you can work along the lead one light or maybe several lights until you reach the point where the fuse blows. For example, disconnect after the first light. Now power up, did the fuse blow? If not the short is after the first light. If it blows, it is between the J box and the light and so on. Also don't forget to check the connection for each light at the light itself.

When I have to trace stuff like this, I always take it one step at a time.

Steve

 

does sound like a marker light is shorting out to me.


Heck I'd probably remove all the bulbs and put a fuse in and one by one see which it is.

 

What do you have for taillights on this trailer? are they sealed or do they have 1157 bulbs ? Ive seen many 1157 bulbs turn in the socket and short the taillight circuit.

 

I will have to try this tomorrow. Only 12 bulbs to pull and check.

 

They take a 1157 bulb. They are the original lights. Trailer is an 2001. These are the lights I have.

Bargman Recessed, Double Tail Light - 84 Series - Red - Black Base Bargman Trailer Lights 30-84-527

 

I would start by pulling the 2 taillight bulbs first and see if the fuse blows. look at the bulbs, some of my drivers change their own bulbs and smash the little pins on the base of the bulb putting them in wrong.

 

Since the short can be anywhere including the socket or connections to the lights, if you get lucky, it will be in a bulb. Rather than go a bulb or two at a time, to determine if the problem is any bulb, if they all are removed and the fuse still blows, it is not a bulb.

Steve

 

Makes perfect sense.

 

First I would buy a whatever amp circuit breaker and wire it in before I attempt ANY of this. Why go through X number of fuses ? After done, if you want, put the breaker and snap in ONE fuse.

 

Just put in an auto reset fuse, will fit right in.

Steve

 

I have never seen one of those. Where would I get one of these? So the parts stores carry these?

 

Well I pulled all the bulbs it still pops as soon as turn on the running lights. Gonna have to dig deeper I guess. I really am at a loss. I have torn everything apart. And checked just about anything and everything I can think of. None of the lights seem corroded or anything.

 

Next I would leave the bulbs out and disconnect the marker light lead in the J box and verify the problem is in the trailer wiring.

Steve

 

Okay. I am not trying to be dumb here. But what is the j box? Is that here the trailer pigtail meets the trailer wiring? With the trailer pigtail unplugged it does not trip the fuse, As soon as I plug the trailer in it pops.


EDIT, I am sorry. It took me a min. Okay. I can dis connect that and try it out.