Battery and voltage Gauge issue

[TedPikes]

I have a 2003 Monaco La Palma gasser. Lately and very randomly when we turn off the engine drop the Jack's and open slideouts the chassis battery voltage indicator on the wall goes blank. At that point the key won't turn on the dashboard lights and there is nothing when we turn the ignition key on. No dinging, no dash lights and no cranking the engine to start. We can make it all work by engaging the Battery Boost switch using the house batteries to start the engine and then it runs normally. At that time the voltage Guage works and shows correct chassis battery voltage, stairs work and interior ceiling lights work just fine. When we turn off the engine the Guage goes blank again and we're back to not being able to start the engine and dash lights are dead. Stairs and jacks won't work. Plugging in to 50 Amp hookup powers microwave and and slideouts work. Last time this happened we were plugged in the problem resolved itself over night. In the morning the voltage Guage was working and all was well for days. Got to our destination today and put Jack's down and slideouts out but when I went to hook us up steps were dead and Guage was blank again. Chassis battery voltage is normal, but ignition, dash and stairs are dead. Don't know what to look for or test to see what is causing this random situation. Concerning because we are 700 (3 days) miles from home! Any ideas?

[d23haynes57]

I would look for a bad battery cable or connection or you actually have a defective battery. Do you have a multimeter? In the failed state, check for voltage at the battery, then follow the cables, to the chassis ground and the one that goes to the starter.

[SafariBen]

It might be happening randomly, but the functions that are affected are all related, so it makes perfect sense that they go off together. I'd probably start at the ignition switch, does it have power? and does the voltage stay relatively constant when you turn the key to on and start? Also, do the headlights work? HVAC blower work? Anything from the ACC position work?


I'd suspect something between the starter and the ignition switch, lots of connections, breakers and relays to check out. The power may not be on a relay to the ignition switch, but the outputs go to "run", "start" and "acc" relays, that may be fed off of one.

[d23haynes57]

The Boost system making it work. Back to the chassis battery and wiring.

[TedPikes]

Thanks, Battery is fully charged and usually the problem is resolved in the morning after being hooked up to 50 amps overnight. Battery is grounded to the frame securely. Found the fuse box but don't know which one/s might be in the circuit/s that connect to ignition, dash, stairs and lights.

[MPM1979]

The boost system making it work would seem to rule out a fuse as it would not reset. Boost system is basically automated jumper cables. Plugged into shore power overnight reviving things sounds like you have a BIM or voltage relay that allows your onboard converter to charge the chassis battery. Shutting off the engine and everything going dead sounds like you were running on the alternator and the battery was not connected?? Do you have a chassis battery disconnect switch somewhere. It might be a real switch or run a relay somewhere that is intermittently failing. If the battery is in fact charged I would suspect a wire issue between the battery and the ignition switch. Maybe the switch itself. You didn't say if the gauge is mounted on a wall somewhere or on the dash which requires the ignition to be on

[Arch Hoagland]

The compartment under the passenger seat has the engine battery turn off switch. Mine went bad about 5 years ago...the plastic crumbled. I had to replace it.

Do you use that switch very often?

[TedPikes]

The voltage Guage is on the wall with the tank level guages and switchs for water pump and HW heater and above the Intellitec power board. It can usually display both house volts and chassis volts. House volts still shows up when the chassis window is blank. When it's blank nothing on dash is working as well as some ceiling lights. Even when we are plugged into 50 amps. Ignition switch works with the Battery Boost and once engine is running the voltage Guage for the chassis works again. Some times everything works fine for days of traveling and this hadn't happened during snowbird trip except for a couple times in last month or so. It's been hard to narrow down the circumstances that cause it.

[d23haynes57]

Batteries can fail in a way that they will show voltage but can't deliver current. You need to get a meter and follow the path from the batteries during the failed state.

[SafariBen]

I agree, there's only so much we can speculate on logically. It really comes down to taking voltage readings when it's acting up. The chassis batteries, or the ignition switch, or somewhere in between, are all fine places to start.

[David 70]

Are you shutting off the engine before putting the jacks down? If so, you are running the battery down with the high draw of the pump motor. I would suggest leaving the engine running while doing the jacks and the slides. A weak battery could show volts and not have enough to power the engine starter.

[chuckftboy]

I once had a similar problem with an F-53 chassis. While driving one of the battery cells would open from the heat of the alternator charging. I could stop, drop jacks and run out the slides with the engine running which I always do. Then when I shut down the engine and tried to restart...nothing. after about 20 minutes the battery would cool down and everything was normal and the engine would start again.

The battery voltage was always good when I checked it so I convinced myself it was somthing else. Took a shot and changed the chassis battery and never had another problem.

[TedPikes]

Finally replaced the chassis battery today. We'll see how that changes the issues we have faced. Hopefully we'll be done with problems and we are only two days drive from home.

[Arch Hoagland]

Hope all goes well. Let us know how things work out.