Skip to main content ↑ ↓
Topic: Master shut-off switch (Read 445 times) previous topic - next topic

Master shut-off switch

What exactly does the master power cutoff switch located on left side of entry steps shut off?  Would this be a good way to store the coach for a month or so with out any electrical connections?
Thanks,
 Mike
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO

Re: Master shut-off switch

Reply #1 –
The simple and short answer is turn the switch to off and then disconnect ground leads to chassis and house batteries.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Master shut-off switch

Reply #2 –
The "salesman switch" disconnects the 12V DC house batteries.

It is a great way to store the coach

The chassis (engine start) batteries are not disconnected by the switch. Physically disconnecting those batteries, stalling a simple battery disconnect at the ground terminal, or a dedicated battery minder is best for the chassis battery bank.

If using a battery minder, make sure it is plugged into an external power source, not something on the coach, unless your coach is stored connected to shore power

If coach is connected to shore power, the house batteries will be maintained by the inverter/charger. Unless modified, in most coaches, the chassis batteries are not charged when plugged into shore power
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Master shut-off switch

Reply #3 –
The salesman switch disconnects MOST house loads.

But, not all.  Refrigerator for example remains powered.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Master shut-off switch

Reply #4 –
What Brett said!

Check schematic B-2126, (find the one for your year: https://www.foreforums.com/index.php?media/album/schematics.194/) the salesman switch allows power to flow to the 120A breaker; that is behind the large white panel in the storage bay (at least on our coach). 

From that 120A it feeds all of the automotive style fuses at the foot of the bed (again that is where they are in our coach).  It also powers items like the aqua hot/front seats/dash/bay storage lights/etc.  So shut it off and all that goes down.

It does not turn off your freezer, hwh pump, refrig, safety devices, dash memory (radio presets etc), power door locks (which is why some have experienced the low voltage flutter death on those), and some other stuff, the schematic will help you out.
2000 / 36' / U320 / WTFE
WildEBeest / "Striving to put right what once went wrong"

Re: Master shut-off switch

Reply #5 –
Disconnect the engine and the house batteries is the best way to leave it not plugged in.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins