[NotNaturallyAspirated]

Hello all that may have insight...

I have serial 278 and today my master lighting switch no longer lights up my interior lighting. My fridge also is off but yesterday everything was fine. I looked for a Master Light circuit breaker to no avail, this is all off of shore power.

Anyone have any idea and/or direction I should look in?

Thank you in advance.

-Mike

[Fulltiming]

The "Master Lighting Switch" controls only 12 volt lights, no 120 volt. Check to be sure your house batteries are not drained down. It is possible the switch itself is bad but check the 12 Volt House Voltage on the power panel over the drivers seat. If it is up in the 12.2 volt or higher level, I would guess the switch. If the 12 volt house meter is reading less than 12, check the voltage of the starting batteries on the dash. If it is very low also, all of your batteries are drained. I don't know if you have power available where the coach is but if it is, plug in the coach and see if the house battery voltage bounces back up. Otherwise, your battery charger (or battery charger portion of your inverter) is either turned off or it is defective or you have blown the high current house battery fuseable link in the engine bay. Obviously, check the water level in the batteries and make sure the connections are tight and not corroded.

Hopefully you either have 120 volts available or the engine batteries are good enough to start the engine and recharge the batteries.

[CaptainGizmo]

I don’t know about the older coaches. But, our coach is Spyder controlled and the “Light Master” actually is a MEMORY function of whateve lights were LAST TURNED OFF USING THE LIGHT MASTER switch.

So, for example, if I only had a single light on and used the LM off…the next time I tapped the LM on, just that one light would come on.

To force ALL of the lights to come on, I have to PRESS AND HOLD the LM button.

Hope this helps; sorry if it doesn’t.

[NotNaturallyAspirated]

Yeah, it is evidently the house batteries as the meter is indicating less than 2 volts. So I then started my coach to recharge the coach batteries but it wasn't enough time I only got a bit past 8 Volts, but they were low anyhow. That said as soon as I hit ignition and started it, all lights came back on including the fridge.
The thing I don't understand is that I still don't have any lighting with shore power connected as I am set up with 50A 230V; why is it I still don't have lighting if I'm connected to ground power even if my coach batteries are below 12 Volts?

[Fulltiming]

The 12 volt lighting is powered off the batteries. The 120 volt power will NOT power the 12 volt systems directly. The 120 volt system runs a battery charger that slowly recharges the batteries. The reason the 12 volt systems started working when you started the coach was the engine alternator started providing 12 volt (actually around 14 volts) to the batteries AND to the coach's 12 volt system. As your batteries get close to 12 volts, the built in battery charger will provide enough voltage and current to turn on the 12 volt lights but at less than 2 volts, the batteries are acting as a block to the prevent the lights from coming on.

[pairodice]

Also turn on the Battery Merge switch on the driver panel - this can be left while plugged in to connect the house/coach batteries together but should be turned OFF while driving so the engine alternator is not trying to charge all of the batteries - the alternator should only charge the engine batteries. Ours has a 3-position switch - the middle selection is OFF and UP connects the coach/house batteries. The generator will charge the batteries but it is slow as there is usually only a small alternator as far as I know but maybe some of the others can chime in on generator function. You might want to check the voltage in EACH of the batteries by disconnecting them (I know, it’s a pain). If you find one that is under voltage or dead then you should probably replace the whole BANK of batteries so the old ones don’t kill the new one…

[johnkosir]

I think you will find that your house batteries are not getting charged when you are plugged in leaving your merge switch on will just kill your engine batteries as well. my coach is a lot newer than your so I am not familiar with how your works

[Richard]

I am in the camp of leave the batteries UNmerged. Nothing good happens with them merged. If you want the chassis batteries to stay charged, there are many devices that will do that in storage without running the risk of killing all the batteries in the coach, leaving you stranded.

[NotNaturallyAspirated]

Gentlemen I really appreciate all your inputs as it greatly helps educate me on this system. I will have a look at my merge switch and see if I have it in merged position. I know now for a fact that my house/coach batteries are completely shot and that I believe has been that way since my purchase but I hadn't run into any master lighting issues until yesterday. Perhaps they've deteriorated further over time to eventually cause this issue I'm having.

For the time being I put a battery charger on my house batteries, in trickle charge mode, and now the master light and fridge is back on all functioning as before. This is a temporary fix for the day as I'm unsure if this will create another issue with the system or simply just charge (or try to charge) my failed house batteries.

[HoosierDaddy]

Mike, This is what I use for keeping the chassis batteries charged in storage:

https://www.batterysaver.com/store/p78/2365-lcd.html

It would be helpful if you can set up your Signature to include the year and coach number. That will allow other Gurus to answer questions more accurately without you having to supply that info within each question.