no 12v power not working

[gits]

I have a 2018 Thor 22B motorhome. We have been traveling for the a while and have been hooked up to shore power for the last 2 weeks. Yesterday I had to move our unit and found out we don't have any12 volt power when off shore 4 volts with power. Normally I would turn on the 12v power by the switch near the door. In the past you would hear the relay click and the power would turn on. Today it did not. I metered the switch and found that it is pushing out voltage when pressed. I then checked the solenoid and found on the converter side with shore power on was pushing out 13.5 volts on the the battery side it showed only 2.9 volts. with no power it had only 3.0 volts on the battery side. I then checked both batteries and they were only reading 3 volts also. I appears if I am correct that the solenoid is not allowing the voltage thru to the batteries or the lights. Has anyone had this issue before if so any info would help. Also does this mean both my batteries are bad at this time? Without 12v we dont have backup camera or radio.

[Oneilkeys]

That solenoid has gone bad for people in this forum over the years and it sounds like your’s may have also. One other thing to check is the 50 amp circuit breaker in your house battery box. It has a red or yellow flag that should not be showing. It has a button that deploys the flag and breaks the circuit. If the flag is visible, yo7 just push it back in. From your description I do not think that is your problem, but it is worthwhile to check.
As far as your batteries are concerned, if they still have full electrolyte, they probably will be fine after they are recharged. They are built to be discharged.

One other thought, that switch needs power and there may not be enough power in the batteries to switch it on, if you left the switch off while plugged into shore power, it was not recharging your batteries. If they ran down during that time, it may be that when you unplugged and tried to switch to 12v power, there was not enough voltage in the battery to operate the switch. I would try recharging the house batteries with an external charger and see if that solves the problem.

[gits]

Thanks for getting back to me quickly. I checked the power switch at the door and when I pushed the rocker switch on it showed if my memory serves me like 3 volts. Ill try and charge the batteries 1st. I didnt see any disconnect either in the battery box under the stairs.

[koachsf]

Had a similar problem with my 2019 ACE 32.1 - master switch by the door needs to on before you plug into shore power so the batteries will charge - I’m sure you know that - my problem was bad batteries - they would show charged but would drain fast. Decided to go away from the wet batteries and replaced them with maintenance free ones. Problem solved. What I would like to do next is attach a meter to the batteries so I can tell that they are receiving a charge.

[Oneilkeys]

Originally Posted by gits

Thanks for getting back to me quickly. I checked the power switch at the door and when I pushed the rocker switch on it showed if my memory serves me like 3 volts. Ill try and charge the batteries 1st. I didnt see any disconnect either in the battery box under the stairs.

In my Axis and Vegas the 50 amp breaker was outside the box on the left hand side. Your’s might be different, but you will have one. There is one inside the engine compartment (at least for the Axis) and a separate one for the 12v systems in the rear. They protect the 12v systems from being destroyed by an overload or incorrectly hooking up the batteries,

[Beau388]

Originally Posted by gits

I have a 2018 Thor 22B motorhome. We have been traveling for the a while and have been hooked up to shore power for the last 2 weeks. Yesterday I had to move our unit and found out we don't have any12 volt power when off shore 4 volts with power. Normally I would turn on the 12v power by the switch near the door. In the past you would hear the relay click and the power would turn on. Today it did not. I metered the switch and found that it is pushing out voltage when pressed. I then checked the solenoid and found on the converter side with shore power on was pushing out 13.5 volts on the the battery side it showed only 2.9 volts. with no power it had only 3.0 volts on the battery side. I then checked both batteries and they were only reading 3 volts also. I appears if I am correct that the solenoid is not allowing the voltage thru to the batteries or the lights. Has anyone had this issue before if so any info would help. Also does this mean both my batteries are bad at this time? Without 12v we don't have backup camera or radio.

The latching solenoid is powered by the house batteries only. It takes 9-10 volts to latch/unlatch the solenoid. If the solenoid is on the store/off position and the house batteries are below 9 volts, the solenoid will not latch in the use/on position. You can start the coach's engine and let it charge the house batteries for about 30 minutes and usually that is enough voltage to latch the solenoid assuming the house batteries are not dead.

[Oneilkeys]

My house batteries would not charge from the engine alternator unless the use store switch was in the use position. If you let the house batteries get too low you had to charge them to get the switch to throw. I do not know if that is true with other coaches.