Benjamin

If it was a car, pickup or tractor, I'd suspect the starter. On a motorhome, my first suspect is the motorhome wiring. If you can find the wiring on the starter solenoid, and rig a test wire to hot wire it from a safe distance, that will cut the problem in half by telling us if it's the starter not working, or the wiring not supplying the start signal voltage.

See if you can pop the boot back onto the housing, it looks like it just popped loose. An o ring pick will help if it's tight to get back on.

I suspect that's a circuit board with an alarm buzzer that's located there to be close to the driver. One tell tale is the shrink wrap has a hole above that round part. Don't worry about dead end connectors, they built these motorhomes on a common wiring harness that has lots of extra loops of wire and dead ends for other options.

Use a cheater pipe on a breaker bar on the side you can reach, wear heavy gloves and a jacket to reduce the skinned knuckles.

Even with the boost solenoid OUTPUT welded together, the key should still turn the engine off. If there were connections between the inputs to the BIRD, that's where I'd look. For instance, IF the system uses ignition on, solar, or plugged in grid power as inputs to turn on the BIRD, that could possibly short and cause the ignition backfeeding here.

Yes, if leaving the house batteries disconnected eliminates the issue, that is a big step. The boost/BIRD should not do this, because that would not get power to the ignition circuit without the key on. The circuit board would be a better place to start. Especially since you say it started up the first time normally, and then would not shut off, and had been started normally a month ago, and had no work done this year. Had there been any other work done in the last year? even inside the coach if not on or near the wiring?

Sort of. In the context of whether a new controller will squeeze more power out of the existing panel, probably not. The PWM will have a certain inefficiency from the voltage drop at full output of one or two volts. When the battery voltage rises to the setpoint, then the PWM will have a higher voltage drop, but that's because the battery will not take more amps at that voltage, so a MPPT controller will not do any better at that point. An MPPT gets it's efficiency by running on a higher voltage panel string, so making charging voltage at almost any light level, and keeping the panel at the Maximum Power Point longer by keeping the array voltage in the right place to get maximum watts, during the bulk phase of charging before the battery reaches the set point. Once the voltage set point is reached BOTH a PWM and MPPT will choke back the voltage and amps applied to what the battery can absorb at that voltage.

Yes, I'd say that rules out the ignition switch. It also makes it somewhat easier to diagnose because you can look for whatever is supplying that voltage without starting and stopping the engine continuously. Do the gauges come on with the key off when the battery is first hooked up? What about the house battery hooked up but not the chassis battery? What happens if you disconnect the house batteries first, then disconnect the chassis batteries? Does the power go out on that ignition circuit with the house batteries or the chassis disconnected? I'd rig up a 12v buzzer into the relay socket so it's easy to hear when you succeed in finding the disconnect, in case it happens without you otherwise noticing it.

Correct, the panel should maintain whatever batteries it's hooked to as long as there's no significant load on them. You can check by unplugging the shore power, then using the inverter for something large enough to remove the surface charge on the batteries, the microwave should bring them down to 12.5 or 6 in no time, then watch how many amps the solar puts into the batteries before they charge back above 13.5. If the solar is only hooked to the chassis, then turn the ignition on with out starting the engine and run the fan on low to do the same thing.

When comparing RV engines to truck engines or any other engine, they are not the same. It might be the same ISC or C7 or whatever, and might or might not be identical internal parts, but the HP setting is significantly higher for RV's. RV's are considered a lower duty rating than trucks, so a truck that is expected to reliably go 250k before overhaul might only be expected to do 100k in an RV or 20k in a fire truck, or 2,000 hrs in a recreational boat. The ISC put in a truck might get 250HP, while the boat, RV, fire truck gets 330+, and in a farm tractor or construction equipment it might be 200 or less. So you're already dealing with a hot tune and there's not as much room for "free" extra power without shortening the lifespan of the engine like there was when an 855 put out 250hp.

Wise man once say "an RV is a conglomeration of systems wrapped in an enigma" (Steve Lehto on youtube), and you have some sort of cross connection between the house and chassis systems that might or might not be the issue here, but it's a good place to look.

As cbr046 said, the biggest impact would be if you could mount the panels off the roof to shade as much as you can to reduce AC. As Rocketman3 said, some inverters can do exactly what you want, but it has trade offs, and is not simple. With LA batteries you want the batteries 90+% charged, Li you want 50% charge, and neither cycled while connected to the grid, so the inverter should handle all the solar production and put that into the grid, not touch the batteries besides an occasional top up. There are lots of micro inverters that can handle that grid tie if your existing inverter can't be set up that way. Whether it's worth it depends on your KWH cost and how long you expect it to pay off for. And probably most of all, how much you like tinkering with things like this.

Jim, the panels won't "produce" power if it's not being absorbed by the batteries, and if the batteries are full, then they are not absorbing much. Think of the solar charge controller like a voltage regulator on an alternator, the PWM controller is nothing more than a switch, if the battery voltage is below it's set point, it connects the panels and the battery. When the voltage rises above the setpoint, it disconnects the battery. It does this so fast that it maintains an even voltage, but the panels are shut off some of the time at rated voltage and full batteries. On the other hand, 36W from a FLAT 85W panel is not bad. Panels are rated for full sun, that is FACING full sun, not sitting flat, so you'll never get full output on a typical RV setup. Also high temp cuts production, so if you'll ever tip your motorhome on it's side in arctic conditions, you'll raise the voltage ABOVE the panels label and could fry your controller. The biggest difference between current panels and the original ones, is voltage. In the old days panels were so expensive that 12V panels were common, now most panels are 36v, so if you hook a 36v panel to a 12V system with a PWM controller you'll never exceed 50% because the PWM can only deal with the high voltage by turning it off. An MPPT controller can transform whatever voltage is coming in into whatever voltage it feels is best for the batteries, and is relatively efficient at doing that. So the panels can be wired in series for 100-400V with the existing small wires and the MPPT will convert that high voltage to battery voltage while conserving most of the wattage. You'll want the wires from the controller to batteries to be short and sized for the amps of the new controller. Probably a good time to consider lithium also, or at least any new controller that can be set for Li. If you can find some 12V (18V max will be the rating on the label) then you can add more panels with the existing one and controller. Or you could center tap any 36V panel if you're that kinda guy, but then you probably wouldn't be here asking.

I agree with cbro46 above, unless the BIRD is destroyed to an extent that it's contacting other terminals physically, the BIRD remaining engaged should not affect the engine turning on or off. It will connect the house and chassis batteries leading to other longer term issues. I'd disconnect the wiring connector at the ignition switch with the engine running, key off, and see if that shuts it off. Since you've determine that removing the ignition relay shuts off the engine, that narrows down the focus quite a bit. Assuming you've swapped relays with no change. You can now concentrate on the ignition circuit between the ignition switch and the "trigger" side of that ignition relay, which I'm assuming includes the gauges, and might still include the alternator. And definitely includes multiple ground points that could backfeed voltage from various points.

On a 2012 engine, the injectors are each individually electronically controlled by the ECM, so I don't think there is any fuel solenoid to stick. The fact that your gauges stay on suggests that the ignition circuit is hot, if that power is not coming from the ignition switch, then where could it be coming from? After you kill the engine by disconnecting the battery, then later hook it back up. Do the gauges come on with the key in off before the engine is started? And even with the battery disconnected? That would suggest a cross connection between the house batteries or solar and the chassis ignition. If the gauges do not come on with the engine off, then I might look first at the alternator connections or any diode near the alternator circuit. If you have a wiring diagram, trace the circuits that control the relay that shuts off the engine when you remove it, or find what does shut the gauges off.

I edited my post, and might have been typing at the same time you were. Can you confirm the ALTERNATOR and AC compressor are both locked up? If it's still just the AC, then you should be good to go. Unless Sammy turned on the engine before checking the pulleys, there's no reason the clutch would be engaged. If he doesn't have the tools to pull the clutch, leave it for now. The other belt should be the right one.

Bypassing the alternator AND the AC compressor would be a complete cobble job. I'm not saying impossible, but sketchy. Rigging a new mount for the idler would be relatively easy if the AC OR the alternator pulley is spinning freely, because the idler is only putting some side pressure on the belt if you can get the length close, whereas with the idler replacing both the pulleys it's taking 2x the tension of the belt, and if it's not aligned close it will jump off. That's quite a wrench to throw in the gears if both the alternator and AC pulley are locked up. I'd be driving back with the alternator to get it rebuilt or a replacement, or both. Sure would have been nice to know that from the start, but I suppose if you find one locked, you might not keep looking. Highly unusual to have two lock up at the same time. Can you confirm the ALTERNATOR and AC compressor are both locked up? If it's still just the AC, then you should be good to go. Unless Sammy turned on the engine before checking the pulleys, there's no reason the clutch would be engaged. If he doesn't have the tools to pull the clutch, leave it for now. The other belt should be the right one.

You can check the ignition switch if you can use a multimeter and get access to the ignition switch. Could be easiest to remove it, disconnect the wire connector, and test the continuity "in the open". I don't know the HMH or what control system you have or how it interacts with the ECM, but if you can find that info, then you can test the input voltages. Don't forget to test the grounds at the same time.

No, they don't all spin the same way. The water pump is smooth, the back of belt rides on the water pump. The alternator and fan pulleys are both grooved, the ribbed side rides on those. Sammy will know all that, the water pump being driven by the back of the belt has been done by cummins decades and many small cars also.

Show Sammy the diagrams that Dr4film posted above, he'll figure it out. I bet he could move the idler to make a wide range of belts work if he had to. I'd guess the idler is not needed with bypassing the AC compressor. The clutch on the AC compressor is usually replaceable without replacing the compressor, and should spin fine with the power off even if the compressor is locked up solid.

I didn't look through your wiring diagram, but the general rule when wacky stuff happens with electronics is "check your grounds". Bad grounds can cause power to flow places it shouldn't, and do things you wouldn't think of. A power probe is great for checking for voltage where there should be ground, a multi meter works just as well, but not as convenient. Check under load, so with the lights on.

A BIRD connects and disconnects the battery banks, so replaces the DUVAC system in the alternator charging circuit. A BIRD should not affect the alternator, and you described how it produces the voltages that the OP saw with the alternator not charging, and the generator charging both banks when on. Motor homes are more complicated electrically than cars and pickups, but not quite as bad as fire trucks, and way less than military trucks, still easy to mess up. Some Delco Remy models come with optional remote sense and "relay" terminals. Most universal replacement part numbers that would be commonly stocked should have both, but you never know. The 22si, 24si, 28si are all available with the same remote sense and relay terminal that Leece Neville uses for the duvac system.

Your alternator is not charging at those voltages. It could be failed, or it could be a wiring issue outside of the alternator. You'd have to test the voltages at the alternator to find out. I thought a BIRD replaced a DUVAC, so you'd have a DUVAC on older models, or a BIRD on newer models, but not both. IF it's a duvac system, then there are Delco Remy alternators with remote sense that will work with the duvac system. Or it could have been changed sometime over the years. The remote sense is common in alternators, the DUVAC is simply wiring that remote sense to the starter battery to compensate for the voltage drop through the two diodes that connect the alternator to the chassis and house battery banks.

Taliesin was Frank Loyd Wright's house. House on the Rock is an "homage" of sorts? There's so much to see in a state, hard to pick what you might want to see? Rudolph cheese factory is worth a stop, maybe not a long drive if you're not going that way. Plenty of other cheese factory stores. Devils Lake state park, or the Wisconsin Dells (river, not the tourist traps) are worth seeing, but maybe not if you just came from the UP, you've seen that sort of thing without all the people. Lots of rivers to rent canoes or rafts.

Yes, ES compleat is hybrid, the picture on the first page states nitrites, phosphates and silicates, none of which are organic OAT. ES compleat OAT is strictly OAT, Es compleat NOAT has nitrites which makes it hybrid in my book, but it seems they have a separate category for NOAT. https://www.owi.com/binaries/content/assets/documents/brochures/heavy-duty-coolant.pdf Old World Industries is PEAK, and makes many OEM coolants, so I trust their info. Notice many ELC, OAT coolants are actually NOAT or hybrid. If you read deeper into the weeds, you'll find Cat mixing ELC extenders with SCA bases, or Cummins Fleetgard had a procedure to "convert" SCA to ELC OAT type, which would be a hybrid of sorts. As far as I can tell, aluminum radiators are the biggest thing that pushed OAT, so if you replace a copper radiator with aluminum that's a good reason to switch. But if you're still running a copper radiator, then SCA is nicer to your radiator, as long as you test or send in a sample. edited to add: not sure how much I trust this site, but I'll throw this into the discussion as well: https://gmb.net/blog/inorganic-vs-organic-coolants/