Online 20A fuse blows every timeI drive over bumpy roads

HI Guys!

I still love my 2010  5-wide and it is in fantastic shape but, I am having a very strange new issue that I hope you can help me with.  I am able to charge my battery from shore power, and when disconnected from shore power I have all the lights and fan running beautifully off the battery.  The strange part is, 9/10 times. When I trailer my LG, especially it seems if the roads are bumpy, I will arrive with camp with a blow 20 amp in line fuse at the battery.  Once I pop in a new fuse, the battery fully comes to life and works for the entire time at the campground- until I tow the trailer and hit enough bumps in which the fuse shorts out again. 

Any ideas?

Here’s what I have done:I tightened all the connections to the battery,I made sure the fuse was tightly in the fuse case,I made sure the converter was screwed in tightly in the galley

And the battery is only 3 years old.  


Could you also send me the electrical schematic of the 5wide LG?  that will help me understand if something is wired incorrectly.


Thank you!






  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    How do I diagnose if the ground wire is loose or hitting metal when I drive on bumpy roads causing a short?
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    Curious where the ground wire connects to the chassis- my guess is somewhere it is exposed and hitting metal. Anyone who can help me continue to problem solve this would be appreciated! 
  • ljbljb Posts: 15Member
    It's not the ground wire, it's the hot (+) side wire contacting the ground/trailer frame somewhere.  In my Silver Shadow, on the bottom floor, there's a junction box inside the trailer where the connector harness and power lines are distributed to the rest of the trailer wiring.  Inside, there will be a wire buss in there with many ring-tongue connectors tied to various terminals on the buss. Look for such a junction box and check to be sure there are no loose terminals/washers/nuts inside that can move around and contact or cross wires. Also check any boxes containing the circuit breakers and/or charging unit.  If everything's tight in there, look for any exposed wires along the way. BUT MOST IMPORTANT: disconnect the terminal at the battery and shore power cord BEFORE you open any covers.

  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    Thank you!!!! I will explore this this weekend. I have only seen where the battery fits ( at your feet/ behind a panel in the sleeping area). I have never seen a junction box- but it may be near the battery- can u take a picture of your junction box and where it is? Only if it’s not a pita! Thanks again!- Sandy
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    I think I found it!!! Thank you!!!! I am going to secure this wire back in the housing (which split at the end and test it out! It comes right off the junction box! 
  • sheepslinkysheepslinky Posts: 6Member
    That pic is a bit blurry, but try to "strain relieve" those wires. That is, fasten them to the frame (or the wiring loom there), but leave slack where any movement that occurs allows the wire to move without stress.

    Think of it sort of like a rubber water hose -- if it turns too tightly, it will kink, so guide it gently and avoid any situation where it could be pulled up into a hard bend. Zip ties work. Silicone caulk is great for protecting the wire from rubbing where it enters and exits through holes -- also rubber grommets. Heat shrink tubing is useful for reinforcing connections as well. Loc-tite thread locker medium strength is used often to keep screw terminals from loosening from vibration.

    After 9 years of bumping around, it's always a good idea to check out your wiring at junctions, controllers, panels, etc. Also, some connectors used in auto and solar wear out over time. If you see corrosion, you can clean it with some electrical contact cleaner or some rubbing alcohol.

    If you have solar panels, also know that the wires from the panels to the solar controller will be energized with DC electricity, even if the battery is disconnected, which is a shock hazard. Removing the fuse at the solar panel can reduce this risk, or simply identify those wires and be sensible (12-18V DC 100W is unlikely to harm you if you're dry, wearing shoes, etc -- please don't work in wet conditions).

    Have fun.  
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    Thank you- here is a better pic. No solar panels and I’ll wait for Saturday to take a closer look when the weather is dry. Appreciate your knowledge and concern.
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    I took a more inclusive pic of where the short might be ( I haven’t opened the junction box yet)- but see more potential areas where wires may be touching/exposed. 
    What is the black spray like stuff over the wires?

  • TomDTomD Posts: 87Moderator mod
    It looks like waterproof goop that was placed to aid in water proofing the transition from hard pipe to flex pipe. Observation based on pictures provided. 
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    Will rubbing alcohol take it off? I don’t want to use anything with a sharp edge
  • TomDTomD Posts: 87Moderator mod
    I don’t think rubbing alcohol will work.
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    well, i couldn't find anywhere obvious that could cause a short in the hot wire - before having someone take the whole wire out, i am going to take out my battery and test it, and replace it if necessary.  my question is; can i replace the 20amp fuse with a 30 amp fuse for the inline battery fuse? thanks
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    battery tested perfectly.  I’m at a loss.
  • LuckyJLuckyJ Posts: 90Member
    If you re0lce the fuse with a bigger one, syou could get to a piint where you coukd crete a burned wire or worst, electrical fire.

    You need to find out where it is making ground.

    Install a new duse, get someone to watch it and starte moving the wires around by hand.  At one point, it should burne the fuse, so you will be closer.

    Someone suggested to open the junction box, did you do it?
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    Ty! Yes I did look in the junction box - all looked good. The negative connection on the battery was not solid so I cleaned and re tightened that- we’ll see if it blows on the next trip.
  • sheepslinkysheepslinky Posts: 6Member
    Sorry, I was off grid for a while. I hope this is resolved. Even though there are less crimp connections on your 5-wide than my max (so many crimped splices!), a poor crimp on a spade or ring terminal (or a cheap or bad terminal) can do this. Likewise, dust dirt, water, tarnish. Electrical connections get old. Also, wires stretch, etc. Fuse holders actually wear out as well and get dirty. Any connection should be clean and free of oxidization. It's not glamorous, but I spend a LOT of time scrubbing copper and other metals with rubbing alcohol and toothbrushes (or similar).

    Hope it's working for you. 
  • swtptmulliganswtptmulligan Posts: 51Member ✭✭
    Thank you so much for writing and understanding!  Well either the lubing of the kinks or the resetting and cleaning tightening of the negative terminal bolt and eyelet fixed the problem!!! Full lights and fan when we arrived at camp!!! I am sooo happy!!!!
  • sheepslinkysheepslinky Posts: 6Member
    Chassis grounding is often enigmatic. That negative terminal and chassis ground point will always get you. To prevent corrosion there in the future, especially now that it's sparkling clean (and full of galvanic potential), apply some grease or protectant to the negative terminals. A glob of vaseline is traditional and works on battery terminals, but silicone grease, dielectric washers, and special products from auto parts stores all work. If you're bouncing around a lot, dialectric washers may be the way to go, and consider a lock-washer between the nut and the washer above the terminal (no need to clamp it too hard, but it'll keep it from loosening). I put one on to clamp down to my LiFePO4 batteries since they require a consistently tight connection at the terminals as a quirk of their nature. 
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