No 12 volt power

[Jay an Tara]

Hello everyone we have a 2017 3791rd and we went to the camper today and had no 12 volt power. The lights or max air fans would not work. The camper stays plugged into a 50amp service and the refrigerator and microwave both work fine. I connected a battery charger to my batteries and my lights came on. Does this sound like the power converter is bad? If so where is the converter located.. Thanks, Jason Ivey

[DQDick]

If you plug the rig in with the battery disconnect on the converter is off also. On my 2917 the converter is a part of the power box.

[Jay an Tara]

Not sure I’m following you do I need to unplug and turn battery disconnect to off an plug back in...?.

[Daryles]

You dont have to unplug the rv to turn on the battery/converter.
Turn the switch to the ON position
(helps to ignore the word "Disconnect". Picture shows OFF position).

[Jay an Tara]

It was in the on position when we got to the camper today. I connected a battery charger to the batteries and the lights came on. I turned the battery switch off and the lights went out even with the battery charger on.

[Daryles]

Dead batteries?
Maybe borrow a battery for troubleshooting.
Also For troubleshooting, if you have a multi meter,
With shore power on and battery disconnect on,
Disconnect the +ve battery cable and check to see if there is any voltage coming in from the converter.

[Montana Man]

Ive seen where the fuses on the inverter blew. They were 40 amp X2. The inverter (or converter) was buried in the basement behind a bulkhead.

[Jay an Tara]

Just came back from the camper and did more troubleshooting. I found 2 blown 25 amp fuses in my breaker panel. Replaced both of them and everything works perfectly. Thanks everyone

[rohrmann]

Those 25 amp fuses are the reverse polarity protection fuses. They will blow if the battery is connected backwards, positive to negative and negative to positive, even for a second. Your battery disconnect switch does not drop all load from your batteries. The red disconnect handle will pull out of the switch when the battery switch is in the position where the switch is open, and if the switch is closed, the red handle will not come out. You rarely need to have the switch turned to remove the batteries from being connected.

[Dancin Goose]

I had a similar issue and it was incoming power issue. My surge suppressor had lost one leg of power. I removed the suppressor and all worked. One side of my breaker panel was dead due to the missing power leg. The 220v is split between the 2 sides. I would start by checking your power to insure you have 2 legs of 110. Good luck

[oddjobal]

The power switch has to be on. Check all your circuit breakers. Check the GFI in the bathroom. The hunt for the converter is a fun one. I posted pictures of where I found mine in a earlier post. If it is a stand alone, it will have 1-2 fuses and an indicator light red/green. If you have a 12v outlet, Check to see what voltage you have when you are plugged in. Mine was reading 12.1 and every time I turned on a light it dropped about 2 volts.
My converter was under and all the way against the wall under the bathroom with the tabs on one side, under the wall. I purchased a new converter (amazon) and disconnected the battery, took a sawsall to the 12v power cables. The AC plug was in the back of the power panel. Re connected the 12v and the AC. Turned it on and the voltage went up to 14.1 and slowly dropped to 13.4. Everything is working great. Mine was a stand alone unit

[Charlie W]

I had the same issue on my 3701 when I pick that up from the dealer batteries wouldn't charge it was the 25 amp fuses. It's happened a couple times after that so make sure you carry plenty of fuses with you.