Master switch

[Windsport_29_M]

So the light is off and I am ready to travel. The coach batteries will not be charging.
What should I check to fix the problem?

[16ACE27]

Originally Posted by Windsport_29_M

So the light is off and I am ready to travel. The coach batteries will not be charging.
What should I check to fix the problem?

Do you have a voltmeter? Check the coach batteries voltage.

You "MAY" be able to close the "Master" switch by having someone hold the emergency start switch while to operate the "Master" switch if your only problem is dead house batteries.

[Beau388]

Remember the light on the master power switch ONLY that there is 12 volt power to the switch. It does NOT indicate the position of the latching relay at the power center. You have an inverter that will monitor house battery voltage when on. That voltage will tell you the position of latching. With the master power switch in the ON position and the coach on shore power, the inverter voltage should be above 13.0 volts. If it below that the relay is not letting power go from the converter to the battery bank. There is a 50 amp circuit breaker in the back of the battery compartment that could be tripped, but that is unlikely unless you have been messing with the battery cables

[tdpinokc]

Great info from all. I'd like to quote what beau388 posted "Remember the light on the master power switch ONLY that there is 12 volt power to the switch. It does NOT indicate the position of the latching relay at the power center."

This really bothered me on our 2018 Vegas so I installed an inexpensive digital voltmeter next to the so called master switchl (wired to coach batteries under step). Now I can tell if the coach is on shore power or coach batteries with a glance at the voltmeter. House batteries fully charged normally show me about 12-12.4 volts. Shore power on and connected indicated 13 -13.4 volts. Flip the store/use switch you will see the voltage change.

[JohnnyD]

Originally Posted by tdpinokc

... on our 2018 Vegas so I installed an inexpensive digital voltmeter next to the so called master switch (wired to coach batteries under step). Now I can tell if the coach is on shore power or coach batteries with a glance at the voltmeter. House batteries fully charged normally show me about 12-12.4 volts. Shore power on and connected indicated 13 -13.4 volts. Flip the store/use switch you will see the voltage change.

Thanks for the inspiration, I took this a bit further on my Vegas... (During a previous mod I added a on/off dimmer for the ceiling lights that tapped the + source of the master switch) ... With this mod the coach now sports a dual voltage gauge I found on Amazon. The gauge has three wires, two +; one for each display, and a ground. A three wire harness was run to the main power relay. In the Vegas 24.1 and likely others, that relay is behind the main power center; four screws and the power center pulls out and out of the way easily.

The Master relay is connects the coach BATTERY'S to the DC electric panel and Converted/Charger). The Master Relay has two external fused circuits on the relay itself, on mine one is red (12v + Battery side), the other yellow (12v + Coach Converter/Charger).

Connect gauges "Main" to the red wire (the fused side)
Connect gauges "Aux" to the yellow wire (the fused side)
Connect gauges ground to ground.

Result: If both voltages are equal and read 13.4 or greater, the main switch is "On", the AC is on, and the batter is charging.

If Aux >= 13.4 and Main < Aux, the Main Switch if Off and AC is on (Red Light On).

If Aux =0, the Main Switch is off and AC is off (Red Light Off)

If Aux and Main are ~= and >= 13.4, Main Switch is on, AC is on (Red Light on).

If Aux and Main are ~= and < 13.4, Main Switch is on, AC is off (Red Light on).

This arrangement tells me the state of the Master Switch as well as the health of the: Fuses on the relay, the Red indicator light, and the Converter/Charger. Pictures below:

[Kip]

I can’t seem to get the RV to hook to shore power. Is there a switch I need to hit?
I plugged mine in and thought it was working but ran the batteries dead.

[16ACE27]

Originally Posted by Kip

I can’t seem to get the RV to hook to shore power. Is there a switch I need to hit?
I plugged mine in and thought it was working but ran the batteries dead.

Your USE/STORE switch has to be in USE in order for the converter to supply 12 VDC to the house batteries.

The easiest way to see if you are getting 120 VAC shore power to the coach is to look at your microwave display. If it is on you have SP to the coach.

[JohnnyD]

Originally Posted by Kip

I can’t seem to get the RV to hook to shore power. Is there a switch I need to hit?
I plugged mine in and thought it was working but ran the batteries dead.

. Also check breaker panel for a tripped circuit. If the DC converter/charger isn't powered, the batteries will die!

[Kip]

That’s funny because all my outlets were working but the microwave was not.
I have it out now to take to shop to check it.

I did have my switch in USE mode too.

There must be something wrong and shore power not connecting

[Kip]

All breakers and fuses I checked

[16ACE27]

Originally Posted by Kip

That’s funny because all my outlets were working but the microwave was not.
I have it out now to take to shop to check it.

I did have my switch in USE mode too.

There must be something wrong and shore power not connecting

Time to break out a multimeter to see what's really working.

Did the outlet for the microwave work?

How do you know your USE/STORE switch is in USE?

What is the DC voltage coming out of the converter?

[16ACE27]

Originally Posted by Kip

All breakers and fuses I checked

Did you trip and reset all the breakers?

[Kip]

Yes outlet to microwave works.

USE switch was on because nothing works with it off

[Kip]

No but will try that

[16ACE27]

Originally Posted by Kip

Yes outlet to microwave works.

USE switch was on because nothing works with it off

What do you mean when you say "nothing works with it off"?

The USE/STORE switch only controls the connection between the DC buss and the house batteries. The DC buss supplies the interior lights, water heater and fridge control power, the thermostat and interior lights.

If SP and the converter (which is ALWAYS connected to the DC buss) are working properly nothing should change when the USE/STORE switch is placed to STORE except the house batteries will not charge. All the other DC powered items will work.

The USE/STORE switch has no effect on AC powered loads or receptacles.

[Kip]

When I switch to store interior lights or anything works.
When switch to use then everything works but the 110 outlets and AC

[Kip]

So sounds like my converter is not working correct?

[16ACE27]

Originally Posted by Kip

When I switch to store interior lights or anything works.
When switch to use then everything works but the 110 outlets and AC

The USE/STORE switch should have no effect on the 120 VAC outlets or Air Conditioner.

If you have no Inverter than the only thing that supplies your 120 VAC outlets and the air conditioner is Shore Power and the Generator, your house batteries don't come into the equation.

However, your batteries/DC buss do supply control power to the thermostat so if the converter is bad AND there is no 12 VDC from the house batteries due to them being dead OR the USE/STORE switch is in STORE then the Air Conditioner, (and furnace, and fridge, and water heater) will not work even if plugged into shore power.

[Kip]

That sounds right because all works when generator runs except the microwave.

But when I plugged into shore power with generator off all same worked also but batteries went dead