12 volt lights went out

[Dhall0070]

Sorry if this is posted elsewhere. I couldn't find any info.
2019 montana 3811 5th wheel

So. Sitting inside and the lights went out. Not sure why the TV went out TV. And lights on oven. And air conditioner/ heat pump.dometic thermostat. Fridge All this went out.

All 110was fine

So went to checking. Battery's. 12.9 volts. So plugged in truck didn't help.
Starting checking 12 vt with meter.
No voltage inside the panel at all.
Checked red key disengage no power.
Checked breaker and small pergo swith at battery. I have 12 volts.
Turned on converter and fridge works. 12 volts at converter.

So. 1 4 gauge red wire going to red key switch has no power?? Trace it to the picture. Looks like a regulator of somekind.

Unplugged the yellow and white and power Comes back on??
So this is where I'm confused. The regulator looks like it controls the auto level.?? Why would this cause a problem if I'm not using it.? If I leave this unplugged what will this cause??
2019 3811 montana

[Dhall0070]

If you can see the yellow circled

[BB_TX]

My first guess is your problem is at the auto reset circuit breakers at the bottom left of your last picture below your hydraulic fluid tank. Did you check for 12 volts on both terminals of those devices.

A good clear picture of those would help us.

[BB_TX]

The device you unplugged the yel/wht wires is the reversing contactor to control your hydraulic pump direction. Those wires look to have overheated. May have tripped your auto reset circuit breaker. That shouldn’t affect the other things you mentioned unless something is not wired right.

[Carl n Susan]

OK, I am confused by the problem description.

Originally Posted by Dhall0070

So. Sitting inside and the lights went out. Not sure why the TV went out TV. And lights on oven. And air conditioner/ heat pump.dometic thermostat. Fridge All this went out.

All 110was fine

The TV, AC and ridge all run on 120V. So all "110 was fine" doesn't compute. The TV and fridge may be driven by the inverter (which takes 12V from the batteries and makes 120V) but the AC definitely uses only 120V (unless you have added a huge battery bank and solar).

So went to checking. Battery's. 12.9 volts. So plugged in truck didn't help.
Starting checking 12 vt with meter.
No voltage inside the panel at all.
Checked red key disengage no power.
Checked breaker and small pergo swith at battery. I have 12 volts.
Turned on converter and fridge works. 12 volts at converter.

What panel has no voltage at all?
The Red Key - is it in the position where you can NOT removes the key? Is there 12V on either sides of the switch?
What is this " breaker and small pergo swith at battery"???
Turned on converter? Are you referring to the "inverter"? The converter is part of the power panel and it is unusual to have it OFF.

So. 1 4 gauge red wire going to red key switch has no power?? Trace it to the picture. Looks like a regulator of somekind.

Was the Red Key in the position where it could be removed? That switch feeds 12V to converter/fuse panel from the batteries for most 12V devices. If it is not passing 12V, then 12V does not make it to the 12V power distribution panel nor does 12V make it to the battery to charge it. The hydraulic system is powered directly from the batteries and doesn't use the path through the Red Key switch.

Unplugged the yellow and white and power Comes back on??
So this is where I'm confused. The regulator looks like it controls the auto level.?? Why would this cause a problem if I'm not using it.? If I leave this unplugged what will this cause??
2019 3811 montana

What you call a "regulator" is the reversing solenoid for the hydraulic system. That yellow/white wire appears to be one of the two feeds from the switch you press to extend or retract the slides. You will not be able to extend or retract (depending on which one it is) the slides with it disconnected.

Better pictures of the battery compartment would be a big help. Take the pictures in Landscape mode to avoid the rotation issue.

I agree with BB_TX that the self resetting CBs may have failed. But that doesn't explain no 12V on both side of the Red Key Switch. not the loss of 120V to the AC nor why the inverter quit supplying 120V to the TV and fridge.

Here is a link to a 12vdc troubleshooting flow chart:
https://www.montanaowners.com/forums...ad.php?t=86323

[Daryles]

Follow Carl's 12vdc Troubleshooting flow chart in the link he posted.

Start from the battery and go through the two red self-resetting circuit breakers mounted to the wall.

[Lee-CI]

Sounds like a loose connection in the area near the reversing solenoid that got disturbed when the yellow and white wires were unplugged. I would definitely check all connections as well as 12V power on both sides of the resetable circuit breakers. Let us know what you find.

[Dhall0070]

Well. I found a burnt connection at the cord that plugs into the camper from 50 amp source. At 330 am.
Appears to be a loose connection on camper side black wire that caused that. Hopefully I get that fixed and it'll fix all the problems. We will see shortly

[Dhall0070]

Here is what I found

[Lee-CI]

Dang! I suspected a loose connection, but never considered the connection being at the other end of the fiver! Great gob and thanks for updating us with the source of the issue.

[BB_TX]

You are certainly not the first to have burned pins in that connector. A not uncommon problem.

Not sure how that might have caused the issues you experienced, but hopefully it will resolve all your problems.

[AZ Traveler]

I agree with Bill - that is not the likely cause of your 12v issue.

[Carl n Susan]

The bad plug could be part, but not all of the problem. If it dropped the 120V leg for the AC and converter it would explain some. The inverter should have kicked in to power the refer and TV. But they have to be set up correctly (ask Foldbak about it). And the missing 12V at the disconnect switch is still an issue.

It will be interesting to see what happens once the 120V shore receptacle is replaced.

[Foldbak]

I'd love to offer some advice but I'm really unclear as to the issue other then the AC receptacle fried. That explains the 120 volt AC problem but shouldn't affect the 12 volt system at all except for charging the batteries.

If you have an inverter then it should turn on and power whatever outlets are inverted. Not all outlets are inverted. If there's a draw on those inverted outlets then your batteries will drain quickly. Sound like 2 separate problems.

[Dhall0070]

OK. So. After everything I cut the cord plug off. Unhooked the inlet plug on the camper.. Wired directly in with brass lugs and heat shrunk and taped.

Been running all day and haven't had an issue. I turned everything on wide open.. Rechecked the lugs after killing breaker and none of the wires or connections was warm.

I can only assume the plug had loose connections from factory and caused all the problems. Time will tell.

The black wire wasn't all the way in. The red lug was loose.
All I can say to that is wow what a great job from the company.

Either way. I guess the leg of the breaker that was bad was on the converter side. Causing a issue for the charging of the batteries. Once I connected my truck it charged the batteries enough to come on for a few mins then go back out.
So probably been like this for a few days and finally melted enough.
As much as it was a pain to find all this. I'm just glad it didn't catch fire.🔥

[Foldbak]

A common problem. I took my rig to the dealer for an unrelated issue. During their troubleshooting the transfer switch smoked. 3 hours and 2 transfer witches later they found the shore power receptacle wiring was loose....

[Randy E]

I just posted this on another thread . Same issue for us in 2017. Our 3791RD had all kinds of electrical issues. All came back to a melted plug that was never tightened at the factory.

[RMcNeal]

I had read so much about this before we got our rig that I purchased a 90 degree adapter for the inlet side of the power cord right away.
Apparently when the cord is plugged straight into the side of the rig, the heavy weight of the cord will pull down on the plug and can stress the wires and connection. The 90 degree adapter helps to relieve that stress from the cord's weight.
YMMV