Help! 12v issues

Thanks for help guys. Figured out the converter was fried. The battery got so low it wasn't working being plugged into truck. Used jumper cables to get the slide in. Ordered a new lower unit on the converter.

The easiest way I have found to check for mounted in REVERSE POLARITY is to find the word "NEG" or the symbol "-" stamped on the 12VDC battery case. Make sure the battery cable connected to this terminal goes directly to a FRAME GROUND CONNECTION which should be very close to the battery installation. Grab the cable and hand trace it to be sure it goes to the frame ground connection.

If this has happened it will blow those two REVERSE POLARITY FUSES you found blown already and it will also blow an IN-LINE fuse in the positive battery leads very close to the battery installation. You have to correct this problem before replacing any of those fuses otherwise it will just blow them again. Hopefully those blown fuses has protected the CONVERTER.

Once you get it corrected be sure to make those battery termials with red paint or something to identify which is POSITIVE etc... You can TYPE up the word POSITIVE on a piece of paper and wrap around the cable then use clear tape to hold it all in place at the end of the battery cable. That works pretty good...

I always use RED FINGERNAIL POLISH on the cable side of the ring terminals for all of my POSITIVE battery cables.

Roy Ken

The truck 7-pin fuse for the #4 charging pin is independent from the running lights pins AFAIK. Ours is a 40a fuse in a box under the hood.

It sounds more like the battery fuse or little DC circuit breaker on the pos battery cable wire (within 18 inches of the battery under one rule) is blown so your 12v is not reaching the camper panel. However the slide should work. It has its own 30a fuse on its own pos cable that might now be blown too.

The converter could be ok once the problem is fixed. Looks like you need to start by taking the wires off the battery and with shore power on, and those two 30a fuses good, see if you have 13.8v (approx.)

Also check the 120v breakers. The converter will be on one of them. New to you so confirm labels on every 120v breaker--sometimes they get labelled wrong.

Check for any GFCI popped receptacles too. Sometimes the converter is plugged into a GFCI circuit.

Then sort out the battery wiring and check the battery with an hydrometer and your meter.

Good luck. It gets better once the teething problems are solved :)

The fuses are good. The running lights outside work when I hook up the truck but nothing else 12v. I definitely didn't reverse the battery but the previous owner may have. I just bought it yesterday. Could the converter be fried?

What work were you doing? Anything that might cause this?

Sounds like you reversed the battery cables on pos and neg posts, so that blew the two 30a reverse polarity fuses.

Meanwhile the battery died but you still got juice from the truck battery via 7-pin.

Now nothing works because problem not fixed and fuses blown--check truck's 7-pin fuse, camper battery fuse, fix the reverse polarity, re-check the new two 30a converter fuses, see if the converter will now work to make 12v and recharge the camper battery.