1992 Chevy Mallard Sprinter Electrical Problems

ok
#1 all RV house lights, water pump, fans, heater blower, and fridge control circuits, etc.. are 12v and work from the coach/house batteries

#2 you should have (2) or more batteries, (3) is common, (1) for engine/chassis, (2) for RV side

#3 the battery switch, disconnects the RV/house batteries for storage
batteries should NOT be disconnected unless you are 'storing' RV and not using it, 'all camping' needs the batteries connected 'ALL the time', until you get home, empty the fridge and put the RV to bed

#4 good news is you generator and charge converter are working

#5 bad news your house side batteries are dead/disconnected /or missing

#6 the only thing you should do with an inverter is, watch TV, and charge things like phones and tablets etc..

major heavy power use aka microwave , coffee pot, A/C, hair dryer, etc
has to be from generator or shore power, unless you invest $$ in a big battery bank and a large inverter, and even then you will need to run the generator during the day to recharge the power you used from the batteries the night before

a 300-400w inverter, is large enough to handle all your entertainment/ internet needs

most people, just run a separate circuit from inverter to where the entertainment recharge power is needed, that makes it available all the time, with NO switch over issues, cords etc.. needing to be moved

You should check all the batteries at the battery termale . As stated the battery switch should be on. You should have 12.6v or there abouts. NOT 12 volts on each battery installed. If you have 12.6v at all batteries and no power is applied then the batteries are good. If not then plug in to shore power and check voltage on all batteries. Should be 13.x . That will tell you the batteries that have that voltage are being charged. Not all batteries get charge on every RV. Some do and some don't. I am assuming that you only have 2/3 batteries at max, so you would not have a inverter installed. If only one battery nothing would run but a few minutes. If two batteries for the RV side then maybe a TV or something else for a short time.

When you have all AC power off does your refrigerator work? If not when you plug in AC does the refrigerator work then.

Are the battery disconnect switches on?

Krusty wrote:
Sounds like it is operating normally. None of the things you mentioned (fridge, lights, fans) would run off the chassis battery. They would run off the coach battery. None of the 120 volt AC stuff will run off the 12 volt system unless you have them connected to an inverter.

okay so follow up ?s

1. if i connect the 12v dc batteries to an inverter, and connect that to the AC system, i would be able to run the AC stuff off the dc batteries?

2. sorry if this wasnt clear - i cannot run any of the dc stuff (lights in the back, etc) off either battery - they simply do not work unless the alternator is running. does that mean the batteries are dead?

Sounds like it is operating normally. None of the things you mentioned (fridge, lights, fans) would run off the chassis battery. They would run off the coach battery. None of the 120 volt AC stuff will run off the 12 volt system unless you have them connected to an inverter.

RV twenty-five years old with electrical issues is not surprising. Sorry.