I have a 2011 Scamp 13. Just finished a major road trip. After a big rain, none of the exterior lighting would work. 15 Amp fuse blew. I was able to isolate the short to the running lights. All the others work but if I turn on the tow vehicle headlights, zap, the exterior lighting fuze blows. I tested everything. Tow vehicle is solid with good ground and voltage. Grounds on Trailer side all check good. The short is definitely the marker lights (Brown wire). I know the approach is to work backwards, so the first place to check would be the 7 Pin contact (must be good because it sparks and blows the fuse when 12 volts are added. My next step is to examine the entry point to the trailer body. Means removing the galvanized clamp/seal and gaining some play in the 7 pin cable. I'm hoping this is where the problem is (worn wire - water getting in etc). I wonder has anyone else dealt with a trailer side short in exterior lighting? What approach to solve.
Mon, 03/21/2022 - 19:57
#1
Trailer Side Electrical Short
...by hooking a 12 volt light bulb (with the RV battery charged) between pins 3 and 4 on the trailer end of the cable.
Then remove all side and stop/tail lights from their sockets, if one of them is shorted the test light will go out (or get dim) when you remove the shorted lamp. If still lighted, I'd start with the rats nest of wire just inside the RV,( under the carpet on mine) inspect all the wiring. After that you may need to start disconnecting wires to identify the short. You may even see a problem in one of the sockets. Please let us know what you find.
...with finding the short using the awesome troubleshooting notes you provided. I removed bulbs one at a time checking the test lamp each time (no change) and suspect the short is upstream of all the lights. Is this correct? I hope so else I might have to drill out the rivets that mount the markers to see if the fault is at the connection.
I also tested for good ground using a multimeter. I gave the fur ball of wires in the passenger side cabinet a cursory inspection (unfortunately this Scamp has a front bath - thus harder to get at the wires). I also loosened the 7 pin clamp on the outside to get a bit more play and room to work with inside. Nothing obvious on first look. I was hoping to find worn/chafed brown wire but no luck. I'm not sure how to go about checking each wire, but suspect it will be difficult. In back under the dinette seats I was able to trace some of the wiring. Going to driver side rear marker was one green and one white wire (I didn't expect to see that - thought one should have been brown).
I was also able to trace from the outside through the fridge cabinet and back along through the hot water heater area. The wiring appeared to be tightly mounted, no chafing etc. I'm wondering if the fault could be in the 7 pin plug itself.
All said, if you have any tips on how to approach checking each wire in the bundle, or whether the 7 pin plug could be a likely culprit, please share.
Thanks for taking the time to read and assess my problem. For now I will drive daylight only, but not the best solution.
Greg Lamb
and in heavy rain I thought that you would find a problem in the light fixtures. Did you have all of the lights out at the same time? It sounds interesting, wish you lived nearby. It's a simple circuit and should be a simple problem, it's just hard to get to things in an RV.
...one at a time and checked my test lamp as I went. Lamp was still on when all the bulbs were removed. Yes, I simple circuit, which makes this so perplexing. I'm going to get in there again this afternoon and look at the entry point, though because the problem surfaced after a rain, I'm going to look at the markers again (where the wires connect). Maybe wipe them down, though here in Colorado, everything is super dry.
Thanks Kenneth for your help. If a solution comes to mind, I'm game to try anything. BTW my HAM call is NF7H. I don't have a rig at present, but will probably get on the air again soon. Here in Glenwood Springs, I'm in a deep valley so reception is terrible. I sold all my equipment and replaced it with a new banjo and new guitar.
Greg
Greg Lamb
Last year,along with camping and radios, we had banjos, guitars, accordions, telescopes and metal detectors. There is a picture of the event down this page. Hams NEVER have just one hobby. https://www.qrz.com/db/AC0GV
We'll, I removed and replaced the 7 pin cable just in case that might have been the culprit. Still no luck. On a side note, I referenced my Scamp's wire diagram and determined my Running Lights operate on the green wire. Same with Pin 3 (on mine it is green - explains the presence of green on my driver side rear marker). Anyhow, I'm going to go back and use a multimeter instead of a test light and apply your troubleshooting method again. The test light I was using was LED, so it is possible I missed the light going dim since LEDs are binary.
Tracking down the short would be much easier if the wiring wasn't buried and enclosed in the structural fixtures (front bath). I'll let you know how it all goes. Would be a coup to solve this one, especially given the simplicity of the circuit.
Greg Lamb
Quick update - yes, the marker light circuit is very simple and straight forward. The barriers I encountered had to do with routing and color of wires not matching the factory wiring diagram. Anyhow, the culprit was the passenger side lower lamp bracket, not the upper, which I would have suspected. The bracket itself was corroded, resulting in loose metal chafing the positive wire. Isolating the culprit involved quite a bit if digging around tight spaces inside, but in the end, it was repairable from the exterior.
Greg Lamb
Well done.