No 12 v or 120 power

Not enough information.. There are two different types of systems. One MUST have 12 volt or nothing works.

Now, I have the basic 120 volt system for a motor home

Power comes in from the INLET (a "hole" in the outside wall with contacts inside where the outlet end of a cord plugs on) to a box called an automatic transfer switch... IF this switch is not working no 120vac gets through to the RV,,, Generator also feeds the Automatic transfer switch by the way and if it does the switch is SUPPOSED to transfer over to generator power...

To test. First make sure you have power at the outlet you plug into. Find the switch, using a volt meter or 120 volt test lamp test for voltage from the HOT lead(s) to neutral on the SHORE input, (May be marked shore or mains) and on the LOAD output. NO power in = cord, wire, inlet, outlet or external to motor home issues.

Power in but not out, Bad ATS

On my coach the next stop is the MAIN circuit breaker(s) in the power distribution panel (My rig is 50 amps)

SOME coaches have Energy Monitors, Or Surge Guards Some have Energy Managers (mostly 30 amp on this last) and Other than testing for power in and out, on the first.. I can not much help you. SOME of these systems are operated by 12 volt battery power. Some are not.

If you have 120vac to the breakers.. Then you do not have a "no 120 volt" problem, you have a not tested (more than likely) problem or a problem IN the breaker box itself.

12 volts

120vac is supplied to a device called a converter, MAY BE ON THE BACK OF THE Breaker/Fuse box (if both are in the same box) may be elsewhere (As mine is) this CONVERTS 120vac to 12vdc. to both run lights and charge batteries.

Make sure it's getting 120vac and measure it's output.

There are fuses, usually a pair, usually 30 amp In/On the converter or the right hand fuses on the fuse panel. (Usually right hand)

Charge your batteries using an external charger, (SMART automotive type) and see if this gets 12 volts back. If it does, find that converter and it's fuises. if not, you are in for a "Where did it go" session.

I recommend a test lamp.. I have 4

One is a device I got at a Auto parts store, looks like an ice pick with a wire coming out of the transulent handle, you can see a light bulb inside the handle. LIGHT (Bright) is good, dim or dark not good.

I have one I made using a license plate lamp and a license plate lamp socket socket.

One I made with a 50 watt MR-16

And a 50 watt 12 volt "Trouble Light" (Long cord makes it harder to use though)

These all test under differing load conditions, making for a much better test.

Clip the wire lead on to a known good ground and probe with the point of the ice pick type. As I said, Light = Power

Follow the wires, check both ends of the wire.. I had one solid length of wire that showed BRIGHT light at one end, 12 volts on the volt meter at the other end but... No light Yup, wire was bad.

Sounds like you could have two problems. I can only go off my guess based on how my rv is setup. If you have no 120 volts from shore power or generator then you could have a bad transfer switch. If you have no 12 volts to your lights, from the batteries, then you need to check your batteries to see if you have voltage.

You also have 120 volt circuit breakers inside the coach somewhere and on the generator.

We need more information

MH was connected to shore power all winter. Went back in end of march to check . There was no 120 power. All the outlets and appliances no power. Checked circuit breaker every thing was fine. Unplugged from shore power a month ago. Since then Now I start generator once a week for approximately 30 mins. Went back few days ago now no power to anything. Started genny but nothing. Today connected to shore power again and will go back tomorrow to see. To make matter worse the radiator hose that goes from reservoir to top of radiator cracked. Just put some gorilla tap on it until I take it to shop. Thanks:@

Uh, all of the above. You have to tell us your situation. Are you plugged in? Genny? Battery disconnect on? What coach, genny, converter?

Have you cycled your battery disconnects? These would effect the 12 volt sysyem.
Are you connected to shore power? Do you have a genset and have you tried it?

Just have to ask, are you plugged into a source of 120 V AC power? Or are you running the generator? Are your batteries fully charged up to 12.7 volts? Answer these questions and we can go from there.

Mahakal wrote:
Hello everyone,
My MH does not have any power 12v or 120v. MH starts promptly. What could be the issue. This is my first year with MH. Any suggestion Thanks:(

No power at the pedestal or breaker off?
Coach main breaker off?
Coach converter charger or inverter charger off?
House battery switch off?
House batteries dead?
Will holding in aux. boost switch while engine is running, produce 12v power to the lights?

What troubleshooting have you done? Start at plug, cord, and on to the breaker box.