New MPG Owners, Question on 12 Volt Battery

Hello! We just purchased a 2012 MPG (greag condition) and we’re figuring things out as we go. This is our first camper of this type!

We put a new 12 volt battery in and the dome lights don’t work. (They should work off the battery, right?). We’ve searched but have not located any bypass switch. We checked and reset the breakers. Not sure what else to do. Everything works fine when plugged in to power (one exactions- see below).

Any suggestions?

Possibly related- the hot water heater isn’t working. We’ve read the HUG. Something somewhere said perhaps the battery is needed in order to light the pilot. Is this right? Water comes out of both handles- just not hot.

Thanks for the help!
Matt & Brenda
 

danemayer

Well-known member
Hi Matt and Brenda,

If I'm following, the dome light works on shore power, but not when unplugged. And the water heater doesn't produce hot water at the faucets whether on shore power or when unplugged.

You probably have a couple of small 12V DC mini-circuit breakers near the battery (see attached picture). One of them is a manual reset and has a teeny-tiny reset button as shown in the picture. It's hard to see, so you may have to run your finger along the edges. When that breaker is tripped, the battery power won't get to the interior to power the lights. The reason the light works on shore power is that you also have a Power Converter that changes 120V AC into 12V DC to power the 12V DC lights, thermostat, furnace, water heater circuit board, and refrigerator.

If the trailer was winterized before you got it, the water heater may still be bypassed. It may be working, but the hot water in the tank isn't flowing to the plumbing fixtures. You'll have to de-winterize. Your trailer probably has 3 bypass valves close, inside, close to the water heater. The valves on the hot and cold lines attached to the water heater (on the inside surface) need to be open. There's also a crossover line between the hot and cold. It needs to be closed. I've attached a picture showing the valves on an MPG. If you can't find the valves, perhaps another MPG owner will chime in with a pointer.
 

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Thank you! We found the tiny reset button. Didn’t work last night but it works today! We’ll take it. It appears everything is now working! Thanks folks!


Hi Matt and Brenda,

If I'm following, the dome light works on shore power, but not when unplugged. And the water heater doesn't produce hot water at the faucets whether on shore power or when unplugged.

You probably have a couple of small 12V DC mini-circuit breakers near the battery (see attached picture). One of them is a manual reset and has a teeny-tiny reset button as shown in the picture. It's hard to see, so you may have to run your finger along the edges. When that breaker is tripped, the battery power won't get to the interior to power the lights. The reason the light works on shore power is that you also have a Power Converter that changes 120V AC into 12V DC to power the 12V DC lights, thermostat, furnace, water heater circuit board, and refrigerator.

If the trailer was winterized before you got it, the water heater may still be bypassed. It may be working, but the hot water in the tank isn't flowing to the plumbing fixtures. You'll have to de-winterize. Your trailer probably has 3 bypass valves close, inside, close to the water heater. The valves on the hot and cold lines attached to the water heater (on the inside surface) need to be open. There's also a crossover line between the hot and cold. It needs to be closed. I've attached a picture showing the valves on an MPG. If you can't find the valves, perhaps another MPG owner will chime in with a pointer.
 
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