Hi allHaving some weird power issues because I decided to try and sell my TT. Here's a run down:While camping this summer, we moved from a powered site to a no power site. Upon arrival at unpowered site nothing worked at all. We found that the 30 amp inline fuse (the one near the battery on the positive cable) was dead. We replaced it and it blew immediately, replaced with a 25 amp (it was all I had) and blew again. We struggled through three days in the dark, then moved to next stage of the trip with full power.Everything thankfully worked again (absolutely everything) once we had shore power. We did not replace 30 amp fuse.We got home and again, nothing worked even when on shore power. Totally dead. A few days later I tried plugging it in and miraculously everything worked again. We replaced the 30 amp fuse and it didn't blow. Trailer worked well off battery or shore power - I used absolutely everything and no issues.Trailer sat for five days. I went to put some stuff away today and fuse is again blown and it's all dead. And now when on shore power only outlets work (tv and microwave). Fridge, awning, slide, power stabilizers, lights, radio are all dead. These worked last week on battery and have always worked on shore power.Tried a different battery and it blows the fuse also. I have crawled underneath checking out all wires for a short and found no issues.I called local RV service place and got a lot of questions but at the end he said - I have absolutely no idea. Now that nothing works on shore power, I am thinking converter but have never replaced one so I have no real idea.We can't find a wiring diagram for this TT: 2010 FunFinder X210WBS. Apparently Cruiser RV don't release them.Thank you in advance for any guidance, tips or ideas. We are at a loss!

Battery hooked up backwards.Sometimes the wire colors aren't helpful so you need to verify the neg/ground actually goes to the frame.

It worked without issue for five trips this year, before these issues and has been connected in the same way for seven years (I remove the battery in the winter). I have labelled wires and put a label on the battery about connection order (from info I copied off here) so I am very confident it is connected correctly. Boyfriend is a mechanic and he has verified this also.The positive wire has the fuse and it is connected to the positive post.

From the symptoms described and assuming no faults you can't see I'm guessing a faulty charging module in the converter, it's putting out enough current to blow the fuse.

afidel wrote:From the symptoms described and assuming no faults you can't see I'm guessing a faulty charging module in the converter, it's putting out enough current to blow the fuse.Disconnect battery POS cable at converter.Then with AC power measure Converter DC outputShould be 13.2V DC without any load Also check battery cell levels.Use a hydrometer and measure each cell specific gravityCould be a bad cell

It may be that you are allowing the battery to completely discharge. When 120V power is connected, the converter is pushing more than 30 amps into the battery, causing the fuse to blow.Allowing all of the parasitic loads to draw from the battery for five days may be enough to completely drain the battery. If you have done this a number of times, there is a good chance that the battery is now bad. I'd suggest to replace the battery and adopt a regimen of disconnecting it when stored between trips. Installing a disconnect switch makes discharging go away, also.If the battery fuse is blowing with no 120V connected, you must have a short somewhere in the 12V system. It may be from a failed converter but that is not typical. You should inspect and make sure that the 30 amp battery fuse is the only circuit protection from the battery to the distribution panel.

Blown 30 amp battery fuse and no power | Good Sam Community

20 Replies

wnjj
Explorer II
Aug 24, 2017
That's great news and thanks for the update. So that makes 3 that's I've heard of. (Yours plus the 2 in the thread I linked above).

Amazing, considering how simple it should be to keep important wires where they should be. Imagine if automobiles just started shorting wires out in 5-7 years?
Proudcanuck
Explorer
Aug 24, 2017
I am extremely happy to say the problem seems to be fixed!! :)
Service guys found that there was a wire pinched in the section we were wondering about - running from the junction box to the disconnect switch - pinched between floor and frame. This part is in the void of the floor and not accessible unless you start cutting the underbelly open. Has been chafing for 7 years and just started causing issues. I guess I've been lucky,

So that is fixed. Power tongue jack motor died while I was trying to leave and I switched it out with a manual one. And now I it is back up for sale.

Thanks everyone for your suggestions, comments, advice and help! Wow are electrical issues ever frustrating. X-ray specs would help LOL
wnjj
Explorer II
Aug 24, 2017
Proudcanuck wrote:
wnjj wrote:
Was the disconnect switch in "connected" mode when you blew that last fuse? To further narrow it down, first try with it in "disconnected" mode. Then you will know if it's the wire from the battery to the switch or from the switch to the panel, or maybe even the switch itself (if it's mounted to something grounded).

If there's a short on your battery cable, it will pull the whole 12V system down and/or blow fuses in the 120V to 12V converter so fixing problem 1 will probably fix both.

When I put fuse in, battery switch was disconnected. No problem there - all was good. As I pulled the switch out (to connect battery) I heard it pop.

Does that mean it's wire from battery to switch?
Thanks wnjj for your help!!

If it didn't pop until you pulled the switch, that means the wire from the battery to the switch is good and the one from the switch to the panel isn't. If you want to be sure it isn't the switch itself somehow, disconnect the wire from the switch (the one heading toward the panel). If pulling the switch with only the battery wire connected still pops the fuse, it's the switch itself. Otherwise it's the wire you disconnected.
Proudcanuck
Explorer
Aug 24, 2017
wnjj wrote:
Was the disconnect switch in "connected" mode when you blew that last fuse? To further narrow it down, first try with it in "disconnected" mode. Then you will know if it's the wire from the battery to the switch or from the switch to the panel, or maybe even the switch itself (if it's mounted to something grounded).

If there's a short on your battery cable, it will pull the whole 12V system down and/or blow fuses in the 120V to 12V converter so fixing problem 1 will probably fix both.

When I put fuse in, battery switch was disconnected. No problem there - all was good. As I pulled the switch out (to connect battery) I heard it pop.

Does that mean it's wire from battery to switch?
Thanks wnjj for your help!!
wnjj
Explorer II
Aug 24, 2017
Was the disconnect switch in "connected" mode when you blew that last fuse? To further narrow it down, first try with it in "disconnected" mode. Then you will know if it's the wire from the battery to the switch or from the switch to the panel, or maybe even the switch itself (if it's mounted to something grounded).

If there's a short on your battery cable, it will pull the whole 12V system down and/or blow fuses in the 120V to 12V converter so fixing problem 1 will probably fix both.
Proudcanuck
Explorer
Aug 24, 2017
As suggested by wnjj:
- buy a pack of fuses (any size up to 30A) and hook the battery positive back up. If the wire is shorted, the fuse should blow when you connect the switch, even with the positive disconnected from the converter.

Bought 25 fuse pack since the trailer eats them 6 a day...(30amps)
Disconnected psitive wire from panel, put fuse in, connected battery at switch and fuse popped.
So problem #1 - definitely still a short. Thought we'd fixed it, darn it.

Problem #2 - plug in to shore power and only 110 stuff works. Outlets are all that runs. Manually cranking up power stabilizers is the pits.

Maybe solving prob number 1 will improve prob number 2? I sure hope so...
Proudcanuck
Explorer
Aug 23, 2017
We can see the wires to the switch behind a drawer, but only about 6" of it. They look ok but that wire passes through the void under the floor of the trailer and you can't see about 4' of it. The service department tomorrow are going to pull that and run new wire.

Could be chafed or pinched there... we shall see!
budwich
Explorer
Aug 23, 2017
one question, have you pulled the disconnect switch to check the wiring going to and leaving the switch?
Proudcanuck
Explorer
Aug 23, 2017
Thanks shastagary for the tips, I'm just sad they didn't work in this case. We were excited last night when something we did seemed to have made a difference.

Wnjj - I will try what you have suggested. I am hauling trailer to service department Thursday morning and boyfriend is busy in the Combine again for #harvest17 so hopefully I can figure it out on my own.

The service department thought possibly something wrong in the void of the floor so we shall see! It all just guesses.
wnjj
Explorer II
Aug 23, 2017
Could have a wire pinched on the frame like 2 different trailers in this thread:
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/29351903/gotomsg/29396845.cfm#29396845

If it blew fuses when NOT connected to shore power (like the OP said in the first post), it cannot be "too much charging current" or a bad battery. There's a short somewhere up to and including the converter itself.

Disconnect the battery AND the converter positive cable. Leave the battery disconnect switch in "disconnect" mode and then use an ohm meter to check the positive cable(s) to the frame. Check both wires on the disconnect switch. There should be NO connection between either one and ground. If you don't have an ohm meter, buy a pack of fuses (any size up to 30A) and hook the battery positive back up. If the wire is shorted, the fuse should blow when you connect the switch, even with the positive disconnected from the converter.

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Blown 30 amp battery fuse and no power

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