We spend about 6 months in the south and while connected to shore power I have had the 12 volt coach system act up on a few occasions especially when the forced air furnace is operating. The lights will dim, furnace blower slow down to almost stop and when I push the battery monitor panel the indicator lights go from the normal 100 full to about 50% and flicker. This also has ocurred with just a couple of lights on.
I have also noted it takes some time for the 12 volt system to turn on when the switch by the front door is activated.
Any suggestions where to begin trouble shooting?
I replaced the house batteries 3 years ago and the engine battery last fall.
The coach is a 1996 Monaco Windsor 8.3L Cummins with approx. 30,000 miles.
+1 regarding 1995brave's suggestion. The problem sounds like either low battery capacity or a bad connection but yuo will need a hand held voltmeter and start where suggested. Cleaning the battery connections so that they are silver colored (shiny black is not good)is worth while as a start also and regular maintenance.
You may also wish to check house battery and engine battery voltage with engine running and report those numbers also. Someone may recall the wiring strategy for that rig which would help.