Converter, is it working

For starters, you can unhook the + lead of the battery, plug in the trailer, and see if the inside lights come on. If they do, your converter is working. If not, it gets a little more complicated depending on how the trailer is wired.

Probably no on/off switch. You'd need a volt meter to check it's operation but if your battery charges when plugged into 120V it is working. I installed a digital panel mount volt meter from Amazon to keep an eye on mine, cost about $7 IIRC.

When you plug the trailer in to shore power, the converter should come on automatically.

You need a voltmeter (not too fancy) and be familiar with its use. A working converter will show 13+ volts at the battery.

If you have any RV and don't have "any fancy equipment"= digital voltmeter, BUY ONE.

They start at under $20 and are indispensable for troubleshooting your electrical system.

wolfe10 wrote:
If you have any RV and don't have "any fancy equipment"= digital voltmeter, BUY ONE.

They start at under $20 and are indispensable for troubleshooting your electrical system.

You can get a bare bones one from Harbor Freight or Northern Tools for less than $10. Which is all you need--a voltmeter and an ohm meter for checking fuses.

If your RV has a "cigarette" lighter socket, get one of these

https://www.amazon.com/Charger-Voltmeter-USMEI-Aluminium-Adapter/dp/B07JBWGRQL/ref=sr_1_3?crid=23WPFAGFA0062&dchild=1&keywords=12v+meter+cigarette&qid=1588011466&sprefix=12v+meter%2Caps%2C426&sr=8-3

One way is with the RV on battery, no shore power, turn on some lights. Now plug in shore power. If the converter is working the lights should go brighter.

Turn on a light.

Plug into shore power.

Did the light get brighter? If so, the converter is working.

Two sets of instructions

With most modern converters you can hook a digital voltmeter to the battery before you plug in and then plug in and compare the before/after voltages.

Or you can turn on lights/or a 12 volt fan (Fantastic fan is great) while someone else plugs in.. If it's working you will see the light brighten or the fan speed up.

NOW: there are some older converters like the Old Magnetek 6300.. it's actually two units and one can work while the other fails. One runs lights and fans. the other charges the battery a Relay joins them if you are not plugged in. This one is harder to check and I recommend an upgrade (Progressive Dynamics 4600 replacment for the electronic part of the unit) in any case (or a 9200 if it's a stand alone box)