Lloyd,

First, have you tried starting the generator? It should have its own starting battery or can be connected to the house batteries using the switch on the overhead panel. With the breaker for your chassis battery charger open and the external cord disconnected, check if you see the same indications with the generator running and online.

Also, on your electrical panel above the door, there should be an indicator for reversed polarity. This light will illuminate if you plug into a box where the wires have been reversed. Was it on or did it illuminate at any point?

The drop from 50 to 30 amps indicates that you’ve likely lost a leg of power. There are more things to investigate, but this should be a good starting point.

Best, John

I’m not very familiar with the CC wiring, but just to give you another area to check: our Liberty has two time-delay relays inside the transfer switch—one for shore power and the other for generator power. If one of these were defective, you would likely have no power to the bus at all.

This might not relate to your situation, but I thought it was worth mentioning as a long shot.

Good luck!

Paul,

We have a transfer switch with settings for 30 amps, off, 50 amps, and generator. I’ve never opened the switch box.

We’re still receiving a warning for “low vehicle battery voltage.” What will happen if this continues, and how long can the batteries remain uncharged before they are permanently damaged? I’m tied up for two more hours today and four hours tomorrow.

For now, we’re running essential systems on either propane or 30 amps.

LLoyd,

Before I installed my Guest battery charger for the chassis batteries, mine went dead once since they weren’t getting charged while the bus was plugged into shore power. I learned a valuable lesson there!

I disconnected all four chassis batteries and charged them individually with a standard 12-volt car battery charger. It took a while, but I got all four to full charge, and I haven’t seen any adverse effects since.

If you can access your batteries, you should be able to charge them this way.

However, if you suspect that your on-board charger is the culprit, I would disconnect it and leave it off—actually, I’d also unplug it just to be sure.

If your existing chassis battery charger is causing the problem, eliminate it completely from the circuit and plan for a replacement. If you can fully disconnect it from the batteries and unplug or disconnect it from power, and your problem goes away, then all you need to focus on is getting those batteries back to full charge.

Lloyd, your electrical setup isn’t the same as mine. I have one 50 amp connector and an automatic transfer switch, but the chassis setup is likely similar.

I recommend checking the four starting batteries to see if they are all fully charged. If one or two are bad or all are dead, that could be an issue. Disconnect the rear charger until you sort out the short in that area, then charge the batteries and get the bus running. You can jump-start it, but not with a 12-volt car battery. Once you get the bus running, you can move to a different power pole to check for issues with the original post.

If you have good service on the 30 amp cable/switch position but not on the 50 amp, there could still be a wiring issue at the pole or the cord. Clear that up first by checking with a voltmeter for 120V on both legs coming out of the power cord. Then, check the plug on the bus with the switch set to 50 amp and look for a short to ground on one of the line connectors. Make sure everything is unplugged when you do this, and ensure the generator or inverters are not online.

Do the meters over the entrance door show 120 volts on each leg when connected to the 30 amp plug?

Do you always turn off the electric when switching the source selector? A burnt contact could be the problem.

Do you have the owner’s manual with the wiring diagram for your coach?

Mike, all four of the chassis batteries show 10 volts when I tested them. I’ve disconnected the 24-volt charger. John W and I tested the power pole, and it is fine.

I am recharging the batteries tonight, and we will drive to Tucson on Thursday to see Chris Snyder, who originally built the bus and knows its systems.

Lloyd,

I received the same “B—- in the Box” message from my 1991 CC. In my case, it turned out to be a fault in the shore cord. The shore cord had a burnt connection from a previous owner that failed early in my ownership. I took the cord to West Marine, where they installed a new end plug ($100 instead of $600 for a new shore cable), and I haven’t had any further problems.

You should also take the 50 Amp Marinco plug on the side of the bus off to ensure all wiring connections are tight. Over time and with many bumpy roads, it’s possible that one leg of the 50 amp connection has come loose. The loud pop could have been the moment of separation between the Marinco and the internal coach cabling.

Hope you find it soon so you can have some peace of mind.