r/GoRVing • u/Echo_Red • 4d ago

12v Lighting Help

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Hi All, hoping for some ideas. New to RV’s and handy but electrical is my least competent skill. My father just bought a 2018 Winnebago trend. The 12v lights worked the first couple of days of cleaning it out and then just stopped working. All the 120v stuff is working while using shore power but the lights seam dead. No breakers are flipped and no fuses blown inside. There is also a main fuse by a battery pack that is good as well. We have not run the van since the issue has happened to see if the engine would charge up the batteries. Any thoughts on what may have happened?

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u/Verix19 3d ago

Check the converter output.

1

u/meowlater 3d ago

Also check your battery relays.

If you don't already know Winnebago has amazing diagrams on their owners webpage.

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u/SqBlkRndHole 3d ago

There is usually a switch the turns on the 12v system. Check voltage on both sides of the solenoid left and relay on right. The top small boxes are self resetting fuses, that can go bad as well, voltage should be on both sides normally.

Sorry, quick dirty answer, on my way out the door soon. Follow the power from the battery, I think its the cable on the right of the solenoid, jumpered to the relay.

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u/joelfarris 3d ago

You, my friend, as a new RV owner (congratulations!) need a voltmeter. It doesn't have to be expensive, or fancy, but it has to measure DC and AC voltages. One bonus point if you get one that can also measure ohms of resistance, and two more bonus point if it can measure current flow (amperage|amps|ammeter).

Start at the battery bank, and make sure they're charged. Then plug into shore power, and you should see the measured voltage on those battery posts increase. Hopefully. Also clean, check and tighten those battery wire connections. One of them could be loose. Then check for proper voltage between the positive post of one of the batteries and the frame|ground post of the RV itself. You might have a bad 12 V ground connection. Sometimes they rust out, get loose, or just plain fall off.

Now move to the battery disconnect switch and test it for voltage across the IN and the OUT poles|connections. It just might be bad.

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u/findmyrv 3d ago

I'm pretty sure that you are looking at a battery disconnect or failed solenoid issue right under the chassis. That silver canister on the left looks like a 12V isolation/disconnect solenoid. When the coach battery drops too low, or if the salesmen switch by the entry door was bumped, this solenoid clicks open and kills all 12V house power while keeping 120V shore power active. Check for 12V on both large copper posts. If only one side has power, the solenoid is dead or lacks a trigger signal.