lights working in coach with battery So switch off

It would appear that a previous owner has wired the lighting in by going around the disconnect solenoid and wiring direct to the battery. You will just need to do some investigation to find where they tied in and move it back to the dead side of the solenoid.

If you have a small switch panel where you enter the RV that has a porch light switch and the battery disconnect switch, I would suspect that to be a likely spot to pick up direct battery power from the hot side of the disconnect switch.

Are you on shore power?

Travelin2,It has worked properly in the past. Turn the switch to off, all power turned off. Something has happened,:::::::LadyRver, No, I am not connected to shore power. Just don't know what has happened. HELP

Do you have a road side assistance which has tech service to call? I have done that in the past.

We have at least one rv tech on here, maybe 2...hope they see this and reach out.

Edited by Barb

It sounds like you have a bad "12V Battery Isolation Solenoid". It is the thing that makes the loud "click" when turning the house power on and off. Whether clicking or not, something inside might have failed and it is stuck in the "on" position. They generally look something like this.


There are 3 & 4 terminal versions available but 3 is more common for your application. One terminal is for power coming from the house battery, another terminal is for the power going to the house. The 3rd terminal is the wire to the control switch. See if you can locate yours, then find one on-line just like it. Disconnect your house battery before taking off any terminals.

For trouble shooting purposes, I suggest tapping hard on the solenoid with a small hammer but do NOT dent it. The "jolt" might just free it up internally. If it works again, you know for sure it is your problem.

If you are good with electronics, you can measure the voltage at the output terminal using a volt meter. A primitive method would be using a 12V light bulb to ground. The input terminal from the battery will always have power. The output terminal going to the house should not have power when the control switch is turned off.

I had a solenoid fail in our first motor home. Something shorted inside it and it got so hot that it charred the firewall it was mounted to, and also melted the wires around it. My point here is, if it's not working right, you really need to replace it for safety sake. You don't want to just forget about it because your RV runs the risk of catching fire. That is unless you disconnect the battery that supplies power to it.

When you refer to "coach battery switch," are you referring to the battery disconnect switch? Or the on/off switch? As previously suggested, if the porch light and interior lights remain on after you have disconnected the coach battery, then that would most likely indicate that they are hard wired directly to the coach battery, or maybe even the engine battery, which would be extremely rare, but possible.

Ron has it right, it's the battery isolation solenoid. Mine died sometime in the last year and I've decided it really doesn't matter much for me since I have it plugged in all the time when it's not being used. You do need a modern converter if you want to leave it plugged in all the time; otherwise, the overcharging will kill the house batteries.

First Off, I do not leave it plugged in all the time, It sits under a metal shed that I had built just for the coach, I have an electric cord that I use to plug in a Battery Tender to keep house battery charged. I have one 12 volt battery for the house part and a battery for engine. Mounted next to battery is a simple cutoff switch, used to cut battery off when not in use. Ron may be the closest to solving my problem, if I could find the solenoid that he is speaking of, so far no luck. Thanks to all for your help. I have had the coach for several years and have never ran into this before. At the present time, it is 96 degrees, with a heat index of 105, so it is a little hot to be messing with it. Gonna try to find the solenoid Ron was talking about . Any idea of location?? Thanks to all of you, it is gotten me puzzeled.

The solenoid switch on our Tioga is located in left part of the battery compartment under the removable cover by the entrance. BTW, we have a modern converter charger but the electrolyte level dropped below the plates over a few months when I forgot to check it when rig was connected to 120 vac power.

Bordercollie wrote:
BTW, we have a modern converter charger but the electrolyte level dropped below the plates over a few months when I forgot to check it when rig was connected to 120 vac power.

That has been my story too. It seems my intelligent Tripp-Lite inverter/converter is not so intelligent. We have owned our rig for 10 years now. I kept the rig plugged into 110V over the winter just that first year, and never did again. I instead charge them a few times during the winter months using a separate smart charger. I feel so much better managing our batteries with it that I use that charger on trips too since we usually don't have shore power, relying on generator power when staying put for a few days or more. It charges much faster than the house converter and nicely steps the charging amperage down as needed, then stops when complete.