1. Genny? That's a tough one, I'd tackle it myself if you can get to it. On ours, except for routine maintenance, I'd have to drop the unit out the bottom of the rig to access almost anything.
2. Refer? Many times it's the main board, you can replace them yourself fairly easily. If it's anything more than that, and you're going to be plugged in most of the time, consider putting in a residential unit. I rarely use mine on propane, we're either running the genny, plugged in or traveling a short enough distance that it doesn't lose it's cool.
3. Steps: Fairly easy for a do-it-yourselfer to swap out. If it's the motor/gearbox combo, many of them are repurposed car window motors. I'd take it out and go see someone at a well stocked auto parts store. If it's the stairs themselves, you should be able to get parts from the vendor or at an RV junkyard. Not difficult to work on at all.
Time to get out your trusty voltmeter and do some checking. Google: "Trailer wiring adapter diagrams" and you'll find plenty of diagrams showing what the pins should do. Your problem is in one of three places: the magnetic lights/wiring, the adapter, or the coach wiring. Your voltmeter tests will narrow that down pretty quickly. If it is the coach, I'd suspect a fuse is blown somewhere. A new adapter is fairly inexpensive, and the lights wiring is pretty straightforward, likely a connection. Since you have some, but not all, lights indicates that your ground is likely good.
My '04 Meridian has a light module under the dash, near the floor mounted to the firewall. Everything (chassis lighting) goes thru that module. I had similar symptoms, the fix was a new, and updated, module from Freightliner, about $400' as I recall.
First try opening the cover on the hot water heater, check for blockage in the fire chamber (spiders/webs; dirt daubers/nests) and clean all that out. Next, take a pencil eraser and remove and clean all the connections, reinsert. Some spray with NoOx or similar contact cleaner (RadioShack).
If that doesn't work, check the vendor website, I know Atwood has a great troubleshooting tool. The thermocouples or thermostat sensors are most likely to go bad.
Mine was a similar leak, rear basement compartment in a slideout. Turned out to be a seam where the metal support frame and fiberglass wall material met at the rear (towards the center of the coach laterally). Never saw it using the light in a compartment method, but did by using a targeted water spray (didn't take much pressure) to see where it was coming in. It got really wet when driving in the rain, not so much standing still, but did get some seepage even then - probably because the rain could get at it.
That said, I used a butyl caulk (smoothed and tucked into the seam) to seal the seam and it's held for several years now.
Best test is to swap it out and see if it fixes the problem. They're cheap, can't hurt to have an extra on hand anyhow. There are testers for them, but they don't test at the voltages and currents these are running at so they'll tell you if it's really catastrophically bad, but don't guarantee it's good if it tests OK.
As to where to get them - any air conditioning shop will have a variety, as will many electrical suppliers, some old fashioned hardware stores, and places like Granger Supply.
Best is to take it out and with you to the supplier and have them match it up spec for spec. They usually have wires that plug on to the terminals. Make sure you mark the wires, or take a picture, so you can put it back the way it was.
CAUTION: Make sure the power is off to the unit, flip off the breaker, etc. AND short across the leads with a screwdriver or knife or similar to ensure it has been discharged. They can hold a nasty charge for quite some time.
It's really easier than it seems to swap one out, usually takes more time to get to it than to swap it out.
Well, finally got it started. Tried all the filter refill, positive pressure in the fuel tank, raise the front end, prime, reprime, and reprime some more advice. No luck. Finally traced the fuel line up to the top of the engine and removed the one going into the fuel pump(?) - cranked no fuel, but when I cranked the engine I could feel slight suction, so rattached that line and removed the one going from that pump into the engine block (injector fuel rail?). Cranked the engine and got spurt of air then fuel (!!!). Reattached that line, went through the prime sequence, and cranked. Started right up, smoothed out, idles well, ran up to 1200 RPMS and let it run a while. No problems. I guess that line had a bubble of air that wouldn't budge. The line forms an arc from the pump up, over and down to the engine port. Tried it again the next day just to make sure, started right up. Headed out on a short road trip today.
Thanks to all for all the advice. Next time I'll pre-fill the filter (outside holes) like I've done in the past.
Whew! Glad that's over.
OK, so I screwed up:
330HP C7 Diesel Cat engine, changed the single fuel filter and didn't pre-fill, didn't go through the prime sequence.
Started normally, ran for 30 seconds or so then died. Can't get it to start since. I've tried the prime sequence, several times (key on 30 seconds, off, repeat 3-4 times then crank starter for 30 seconds - wait several minutes and repeat) but no luck.
Fuel filter and bowl are full of fuel, so I assume the fuel pump is working.
Any advice before I have it towed to the shop?
With HWH jacks, retraction is less likely a levels problem, more likely a weak spring. Release pressure on the solenoids and see if they come up. If so, it's not a spring, then suspect a solenoid valve. I've got a slow one, I need to replace the spring(s) on that jack.
Have and use PA, usually pays for itself in the first couple of nights of use (around TX, LA and routes to Denver and Baltimore mostly).
Another advantage is that some parks will give a 5-10% discount even if not PA parks - probably not an advantage if you have any of the other alphabet memberships that garner similar discounts at parks.
As others have said, some good parks, some not so much - not a PA issue. I usually use it for quick overnights so quality of the park, within reason, isn't usually an issue.