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Pxr177

Fuse In 12 volt Circuit

9 posts in this topic

I have a class C Fourwinds on a Ford 450 chassis.

My 12 volt system only works on shore power. I have been told there should be an 80 amp fuse on the main circuit right near the battery. This is probably blown. I took a look but could not see anything familiar. I expect I will have to pull out the batteries to get a better look.

What am I looking for?

Where is such a fuse mounted, and what kind of fuse is it.

Thanks for any suggestions.

Paul

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I don't have a Four Winds, but fuses of this size usually are flat with a small round window in the center. The ends of the fuse are connected to studs on fuse holder and the cables are connected to those studs, too. I would start at the positive terminal of the battery and follow the cable into the RV until you find the fuse.

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Paul,

I would check the chassis batteries and connections, look for a disconnect solenoid / relay or the fuse controlling the circuit.

Sounds like your charger is running when connected to shore power supplying 12 volts, but are the batteries charging?

Rich

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The batteries are fully charged. I have pulled a battery out and will take pictures of the innards. if i can't sort it out I will post a pcture.

Paul

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Paul,

With battery installed, use a voltmeter or test lamp starting at the positive battery terminal to chassis ground. Work toward the disconnect switch and then on to the 12 VDC fuse panel. Determine where you go from 12+ VDC to 0.

Brett

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I used a camera to look more closley inside the battery compartment. I got a clear picture showing the part I think is the problem.

There is a HI-AMP Buss 135A breaker in the circuit. Using this info I went to the net and found a video showing how this is used. Sure enough, the breaker was open. I have closed it. Then I disconnected shore power and tried my cabin lights. No cigar, but there may be a delay if the batteries need charging.

Is there any other fuse or breaker near this location?

Thanks for all the suggestions.

Paul

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Paul,

What is voltage at the batteries (digital voltmeters start under $10)?

What is voltage on battery side and on coach side of the breaker?

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Problem solved!!

I had been told quite often that the circuit was protected by an 80 amp fuse. This is not the way it is. On my system, it is the 130amp buss that acts as a breaker. In my last post, I indicated that I had reset the breaker and nothing happened. Today, a buddy and I were looking at the system, and tried again. At that point my dear wife noticed there was no green light on the kill switch ( our RV- and probably most, has a switch to kill all power for long term storage.) Ours is near the outdoor light switch, and I suspect it was turned off in error while the breaker was out, but of course we had not noticed because the 12 volt system was down.

Wifey hit the button, and the 12 volt lights came on. With the three of us working on it, it proved that old Chinese proverb " many hands make light work!"

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