12v not working

First there may be a main battery fuse or circuit breaker that is blown or tripped

Second many low end units of that era had Magnetek 6300 Power distribution center/converter/charger unites.. El-crapo converters but in these units the converter and the charger are differente modules. the charger is small. around 3-5 amps and dumb (it keeps on charging even if the battery is full. thus boiling the battery dry and killing it) and the converter is not much better since it outputs rectified AC which is a long long way from true DC.. But is ok for things like lights that do not care how dirty the power is.

When you unplug there is a relay that is supposed to connect the battery to the lights. It can fail

Recommendation if you have one is a progressive Dynamics 4600 series.. This replaces only the rear portion (The elctronics) of the panel. you keep the same fuses and circuit breaker part but the back part is upgraded to the best 3-stage converter made..

Possibly a bad panel. You've probably already discovered that there are holes or slots in the back of the fuses next to the amperage rating. You can use these holes to poke the multi meter probe into allowing you to take a reading without unplugging the fuse. You should get 0 volts from one slot to the other on the same fuse. On a single fuse, if you measure voltage from each slot to the ground you should get the same voltage. If you find a fuse where there is battery voltage on one slot but not the other slot that fuse is blown and needs to be replaced.

I would take a voltage reading on the battery itself and write it down. Next take a voltage reading on the battery wire at the fuse panel. The voltages should be the same or within about a tenth of a volt. Keep measuring voltage to ground further down the line (The slots on the reverse polarity fuses, the slots on the other fuses) until you find where the battery voltage drops significantly.

I have full power where it connects into the fuse panel. And have .35v on all fuses. If I jump the power from the converter to the light fuse the lights turn on. Would that mean the fuse panel is bad?

Go with Autum_Snowbirds tests. On the surface it sounds like an open circuit breaker or fuse near the battery, But a bit of multimeter testing will help narrow that down.

Joshc1425 wrote:
1996 northland slide in pick up camper

bet t has / had a Magnetek toaster as original equipment...lol

Batteries any good, did you check them?

Joshc1425 wrote:
1996 northland slide in pick up camper

Probably has a 6300 type converter, which needs a battery to filter the "dirty" 12v to run some things like the fridge's circuit board. The dirty 12v is ok for lights and fans.

What was the replacement converter? If a modern type, it makes only clean 12v and you are ok for no battery as a filter.

Meanwhile you need to get the 12v working on battery for when not plugged in. Also check for 12v when you are plugged into the truck and the truck engine is on.

There should be a fuse or DC circuit breaker on the positive wire near the battery, which is the first suspect. Or just a dead battery.

dalenoel wrote:
Helped a friend with slide in camper and we found a GFI way underneath in the rear. Did not look tripped but I tripped it and then reset. From that point on all worked. Saved calling a RV Tech out to the campground.

OP has no 12 volt power without shore power. GFI has nothing to do with 12 volts. It is a 120 volt device.

Joshc1425 wrote:
I just bought a camper not knowing there was an electrical issue and the 12v power does not work. If the camper is plugged into shore power it works. I have power up to the breaker box so I thought it may be the converter but I replaced that and it still doesn't work. Any help is appreciated.

Welcome to the forum. You will learn much here. I'm gonna give you some advice. DO NOT replace a part because you think it is bad,!
Know whether it works or not. Replacing parts can be very costly.

Buy a multi-meter and learn how to use it. Youtube is your friend.

1st, If you have 12 volts while pluged into shore power then the converter is working. Converter changes 120 AC volts to 12 volts DC. A converter is just a glorified battery charger. You musts have a good working battery. Check the converter for two Reverse Polarity fuses usually 30 amps. Measure the output of the voltage Converter at the converter. Then measure the voltage at the battery. Disconnect the converter and measure the battery voltage. 12.6 min voltage required. Battery full of water? Do you have a battery disconnect switch. Is it on?

Lights and control circuits are 12 volts DC = fuses. Outlets AC = Circuit Breakers. Fridge AC/gas. Water Heater AC/GAS. Furnace DC/GAS

AC = Electric
A/C = Air Conditioning.

Good luck

Helped a friend with slide in camper and we found a GFI way underneath in the rear. Did not look tripped but I tripped it and then reset. From that point on all worked. Saved calling a RV Tech out to the campground.

Very simple electrical checks.

Not connected, put meter on battery. Write it down.
Connected put meter on battery. What is it?
Connected put meter on negative and positive output of the converter. What is it?
Your results with those checks will determine your problem most likely.