Parking lights shorting out

[andyfuson]

I am running out of ideas. My trailer began blowing the fuse on my truck when the parking lights were turned on. I know there is a short, but I am having a time finding it. I know the green wire is my parking lights, and I have traced it back to the bathroom area behind a kick panel inside the trailer. I have cut it at that point and now the front marker lights are working. I have removed all of the back markers to inspect them as well as removed all of the bulbs. I also removed the main tail lights and cut the green wires from the back of them. The short was still present. I assume that means the short is between the bathroom and the tail lights, but I cannot seem to access the wire at any other point. After the bathroom sink area is the toilet and then the shower. Any advice on something that I am missing would be greatly appreciated. I hate to think of drilling out panels or removing the shower, etc. when the trailer is only three years old.

Please Help!

Andy

[rickandsandi]

Greetings Andy-

Well the first thing you should have done is pulled out your ohm meter rather than start cutting wires. It seems to me that at this point you may have backed yourself into a corner but there is always help. If I understand correctly you have ruled out the front clearance lights on your AS? How about the front side markers, are they ok? Now when you remove all the marker and clearance lights on the back section of your AS does this cause a short? Or have you isolated the short to one particular wire ou can not get too?

[andyfuson]

Hi Rick,

Thanks for your time. At first I thought the problem might have been in the plug, so I located the wire harness under the fron sofa and I cut the green wire there. When I did that the trailer no longer blew the truck fuse. I reconnected the wire and looked for it further back in the trailer. That was when I found it under the bathroom sink area. I cut it again at that point and when I plugged up the truck and trailer all of the front lights worked fine. When I remove the marker light around the back there is virtually no slack in the two wires that feed them. (one white and the other black) I was able to pull on them just enough to see if they had been damaged where they came out of the trailer skin. I left all of the bulbs out just in case one of them was causing the short. My trailer has the dual LED lights on each side for the tail/stop lights. When I unscrewed them, I could see the green wire going into each of the four LED lights. I cut all four there after I reconnected the wire under the sink. All of the bulbs were out of the back markers and it still shorted. The brake lights, turn signals and hazards all work fine. It is only when the lights are turned on that the short occurs.

Andy

[ROBERTSUNRUS]

Hi, from my experience doing electrical repairs on cars, think back to what was the last thing that was done or happened to your trailer. Any broken light assemblies? Any new dents in trailer? [near lights] Any modifications or repairs done prior to noticeing the short? Most, not all, shorts that I repaired were caused by the last thing done; And a lot of them were caused by a screw through a wire loom installed by the owner.

[boatdoc]

Hi Andy; Time to break out a Ohmmeter and check positive side against ground by following the wire. To be sure that is not the light housing itself disconnect the tail light wire at the light, and with grounded bulb connect the troublesome wire to it. If it lights up fine, it is your light that is shorted. Good luck, "Boatdoc"

[rickandsandi]

Andy-

Sitting here in CT I can only think that possibly one of your upper clearance lights or side markers in the back is causing the proble. I would put the LED assemblies back together then remove all the clearance light units and start checking each one with a meter. Once you have isolated which one is shorting you can move forward from there. Keep me posted.

Rick

[charliejw]

For what it's worth, I had a similar problem with a new 34'. When I put the trailer lights on, they would SOMETIMES blow out on the trailer and my truck.

3 trips to JC from CT said the problem was fixed. NOT.

Went to AS dealer in MA. They said they fixed it. NOT. I picked it up and drove a few miles and tried the lights. Blowout. Turned around and went back to the dealer. Now they had something to work with. Smartly they didn't start by pulling on wires as JC did. They kept testing and found the short. A screw had pierced a wire from the left tail lights to the upper clearance lights. The problem was if you pulled the wire it would come of the short.

The dealer ran a new wire and fixed the problem.

[HowieE]

The first thing I would do is call Airstream and see if they can give you a detailed routing of the parking light wireing for your model. Without this you are just guessing which side of the problem you are on as you open a given fixture. Also ask if there are any connections made in the wireing other than at a fixture. A buried connection will drive you crazy.

Leave the bulbs out while testing, it is highly unlikely a bulb can short, but they will show a path to ground if you are testing with a n ohm meter and cause confusion.

You should see a connection of 2 green or black wires plus the wire to the socket at each fixture since the lights are most likely wired in series. Start at the fixture closest to the bathroom. Open the splice at the connector or cut the wire to brake the series. With your ohm meter test each side of the cut. You should see the short to ground on one side. Now how do you tell which side the short is on? Mark the side that showed the short, leaving the wires cut, and go to the next fixture and repeat the same test. If you sitll see the short on either of the wires it may be between the 2 fixtures or it may still be beyond. If you do not see a short the problem is in the feed wire of the previous fixture and you had put a note on it.

If needed repeat this test with each additional fixture, marking the wire showing a short at each fixture, until you do not see a short. At that point the problem is between the provious 2 fixtures.

This is near impossible to follow just from the text. Draw the circuit out on a piece of paper and erase a line as you cut a wire. looking at the drawing you should see the logic of the test and how it progresses.

Send me a private e mail with your phone number if you have a question.

[andyfuson]

Thanks for the suggestions so far. I guess one thing that I need to do is learn how to use an ohm meter. I will also call Airstream for the wiring info, since the owners manual diagram doesn't give enough detail. I'm not sure when I will have time work on it again, but please keep the suggestions coming. Once I do look at it again, I will certainly post my progress.

Andy

[HowieE]

For what you are going to do get a "cheap" analog volt meter, $10.00 at Radio Shack. Do not get a digital meter because the reaction time is too long.

Set the meter to the lowest resistance setting and touch the probes togeather. Note how the meter immediately jumped to the far end of the scale. While holding the probes togeather you should be able to adjust the meter so the needle rests on the zero point.

For your initial testing this meter jump is what will show a short when one probe is attached to the trailer body and the other probe to one of the wires in question. The best place to attach to the body is through a screw hole because that will be a metal to metal connection. Just touching the body you will have clear coat paint between your probe and the body.

If your problem is a Dead Short it will show with the meter set on zero. If testing on this setting does not show the problem you may have to increase the resistance setting on the meter and repeat the tests. In any case if all the bulbs are out and you see a meter jump you have located the problem.

[andyfuson]

Any chance that someone on the forum knows the wiring layout in the rear section?

[azflycaster]

I would go with HowieE's suggestion of the ohm meter. With all the bulbs removed you should have zero ohms on the green wire to the rear area. I don't know if it's been mentioned or not, but the license plate lamp will be powered by this circut as well.

[Airhog1]

Check the light above your license plate...we had one that was shorting out yesterday and that was the problem...just a thought.

G

[andyfuson]

I actually cut the wire to the license plate light. It only had a single wire to it and there was no slack on it for me to play with, so I cut it to rule out that fixture.

[neil.ervin]

I had the same problem. Surprisingly as it may seem, there was a bad bulb on the trailer exterior. Kept blowing the fuse in the tow vehicle motor compartment.

Actually the bulb glass would rotate around its metal stem. Replace the bulb, no problem since.........

And I was so sure it was the bulb fixture.

[andyfuson]

Thanks Neil,

I had hoped that was my problem. I have removed all of the bulbs as well as cut the wiring loose from the tail lights and the short is still there.

You were lucky.

[HowieE]

The fact that the license had a single wire is important. When you call Airstream for a routing diagram. If they do not discribe that light as the end of a series including all of the tail lights or as a seperate routing from another fixture, and say which fixture, they have blown you smoke.

Unfortunately Jackson Center all to often blows smoke when ask a hard question. When I was looking for parts for my roof vents I have had then claim they never used the parallel lift roof vents and that I had to have installed them.