Electrical issue, a Pop noise on shore power 2019 Vista 27PE

[Bryon Carpender]

2019 vista 27pe 1st gen
Notice that every time plugging in shore power, a pop like noise I’m assuming their is a switch over relay somewhere?

The power surge protector has no issues with the wiring all green

Check in the drivers side shore power cabinet the power cord is ok however under the 1900 box cover found the wires burnt and crispy thought snap their is the problem nope

Repaired the burnt wire suspect that over time the wires came loose and also not long enough on the wire nuts see photos amazing no fire and no arc marks in box so very hot overload

still hear a pop when plugging in shore power my wife thinks one pop in the front and rear can’t tell I pulled out the converter fuse box don’t see any problems

My vista has a separate box to plug into the generator just above shore power wiring box nothing else and the shore power wiring is separate from
The generator and appears to go to the converter fuse box but that’s not where the pop is ?

So where is this mystery pop snap Relay inverter, something else coming from ?

Anyone else experience this issue before?

Amazingly lucky finding this particular issue but yet still another problem to determine the cause of the pop noise ?

 

[Morich]

Yes sir! Looks like you found one bad guy! Kind of scary but then also does make me feel a bit better to know that the arcing should be all inside the metal box and things get shut down before the heat gets out of the box! At least that is design and if we keep things out of the box, it should not go much further.
I was on a safety group for a bit and it was kind of fun to go through things and look at what caused problems and I learned to look for things like where the heat was most intense as the point it started.
Look at the remains of that wire nut on the white neutral in both pics 1 and 2 and we can see the wire nut was holding a combo of solid and stranded and that can lead to trouble if not done carefully. The strands can get pushed in ways that they don't get really wrapped hard and some of them may not have been making contact at all. That can mean the ones left doing the work can overheat and melt the connector.
In 4 we can see the white solid wire was getting hot enough to melt through it's insulation and begin to contact the ground and in 9 it was working on getting contact with the hot side as well. Really close to failing, so the last picture and the tape to help keep any vibration from trying to work the connector loose are a big step up!

But on what the new snap may be? A guess may be needed!

Does your RV have the inverter switch option or just inverter? My thought might be to check the switch as a possible suspect for a delayed snap after plugin in. But do you have the switch?
I ight favor looking at that inverter and for sure the switch if onboard. Possible slow to build to the right power in some way to make something inside snap?
Maybe a relay not in good shape? Some kind of arcing but only one time?
Maybe try plugging in with the inverter in different states, like turned on or off to see if you get a different set of noises?
Maybe depends on how easy to get the cover off? It looks to be mounted on the floor but is it in an inside compartment like under a seat? We get hints of walls drawn in and those may mean more to you if you can look at the real thing! But it does look like the inverter and any switch are under a metal cover. The cord sticking out might be the easy clue for whether you have the switch?

Looking down toward passenger side

from driver's side

from front and own

Any hint of smell when it snaps?

 

[Bryon Carpender]

Spent a while looking over the Winnebago wiring site and seen detail EA

If I look in the 2nd compartment passenger side I see a 110 outlet 12v lamp an electrical connection but no inverter seems like the seatbelt go through a metal plate Makes sense

On the drivers side front compartment I see a panel below the self reset breakers

Guess I have to remove everything as those are the pass through compartments

appears to be wires going up under the sofa in the floor assumption so maybe their is access point hidden?

 

[Bryon Carpender]

Just a noise of pop or snap and you have to disconnect for a few seconds before it pops again so I’m assuming it’s a noisy relay ?

 

[Morich]

I think the inverter and if there is a transfer switch for it, to be inside under the couch. Depending on how the inverter controls are left, I feel like the inverter may be used to change battery power to AC power while not plugged in. Then if the inverter is left on, or there is a transfer switch, it may change as you plug in and let the cord supply power to things that were powered by the inverter.
I would expect the inverter ( and switch?) to be under the couch and just to the right as you enter through that door.
The owners manuals refer us to a different manual for the inverter operation and it should give more details on use. But first step may be to find what you have and if you have the automatic switch for the inverter.

My thought is that you may have an automatic transfer switch but that is not going to be correct if you don't have the switch!

 

[Bryon Carpender]

FYI,
Today explored the operators manual according only inverter on the 50 amp model.

Manually switched off the batteries at the door couch battery off switch.

Not a pop but a ping up front drivers side. Opened the front driver side compartment slide Control bunch of circuits breakers and
A
Panel Humm remove wing nuts nope
Thats The hydraulic and reservoir unit, have to check it later as the jacks are down needs to be up

Anyway the circuit breakers no inverter or solar power breakers.

Tomorrow plan to drop the jacks, Next remove the circuit breakers panel a bout 8 screws have to pull shore power and switch off battery

My suspicion is a to expect to find a 12v solenoid crossing fingers

 

[Morich]

Sounds correct to find a solenoid directly behind breakers near that spot.

There are two builds for that year and RV, so I snipped both to let you look at the difference in this spot.
Early with no battery disconnect relay shown here!

Or later has a 7th digit of 2 and has disconnect relay shown here!

This solenoid is where the connection between the chassis and coach batteries is done. when we have the key on or when we have the dash switch for boost held. So the big lugs are chassis on one side and coach on the other with smaller wires LR and FM on small lugs being the wiring that controls this relay!
Pushing the switch feeds 12V on LR and goes through coil inside this solenoid to ground on FM and that slaps the big contacts together.
Good place to be aware of as it takes a beating and can often be a problem if your coach batteries stop charging as you drive? The contacts close every time we start the engine and if the coach batteries are down a bit after a night of camping the current and arc can be pretty heavy when they close. That arcing does tend to burn the contacts sooner than we might like!

Loose wires or maybe just hearing the solenoid close and it is normal???

 

[Bryon Carpender]

Yes that’s the location I’m referring too perfect.

Directly below is the hydraulic reservoir
Will lift the jacks then pull shore power and disconnect the batteries at the couch switch and hopefully remove 8 screws and verify why it’s so dang loud cross fingers.

And then check and add fluid to the jacks I doubt anyone has checked it since 2019

 

[Morich]

Sounds like a plan!
I might warn you about a problem I see with the wiring diagrams on this area?
they show up here but the early and late build are shown the same, so we don't know which you will have and it is drawn about as bad as I've seen and that makes it harder to spot the true story.

I know this area as it is the way many of the Winn of that age group handle the connection to get charge in the coach as we drive or when we push the dash switch for a "jump start/ boost"!

At left is the mode solenoid that dos that job. Blue marked wires are the small wires LR for bringing 12v and FM is ground and also should show tied to the mounting screw. Belt and suspenders type thinking!
But this drawing shows it on the big lug where the chassis battery cable goes. No small ground wires tie to the positive of battery! Ba drawing but that is just a small one I disagree with the way they drew things.

At right, if you have this disconnect relay, there should be three wires/cables on the left side of the relay.
I drew them all as red lines. There are wires that go in at top to control this relay when you use a battery disconnect switch! But they drew a bunch of wires crossing this connection for this relay and that just confuses thing. They should not draw lines across other connections! Ignore the things I marked in orange?
Main points are that coach battery comes in to left side of relay and then another short cable takes it across to the solenoid!
When we have this relay closed, the coach power can go through the relay contacts to the right side to power those three things. K and KKF go to fuse panels to power RV things and there is also a connection to a mega fuse that goes to the generator to start it!
All three of those get cut off when we open the relay! But that can involve a trick to know about turning coach power on/off!
There is a line I marked in red on the left side of this relay and it is connected directly to the coach battery! It stays HOT to power safety items even when relay is opened!
This wire GJ often goes to a little 6 amp fuse and it is the one that can run the coach battery down when we thought we stored the RV with all power disconnected! Feeds the LP detector for one. If that has a small green LED, you can see it is still on when we think we turned things OFF!

This is a good area to know because we get loots of problems that trace back to this pair of things.
In your case they made it harder to sort when they drew lines across places they don't connect!

If you want to do a quick check that the solenoid does actually move when it gets 12v, you can touch a wire from either big lug to the small center lug and you should hear or feel it thump! That can't say the contacts are good but at least you do know it is alive enough to jump!
And when it jumps, the left and right big lugs should suddenly read the same voltage as they connect together!

 

[Bryon Carpender]

Well I’m not surprised found another meltdown black wire goes from the wire bundle into the wire space and goes up through the kitschy side by it self ? Nothing tied to it passes through

This black wire was behind the big solenoid terminal left side, had this wire behind and I’m assuming rubbing against the terminal very messed up likely electrical tape (what is it and where is it going no label) I’m assuming a chassis ground?

Moved it out and away bummer still getting a pop

Have to look at the photos their is another device see photos

Time to do some multimeter tests still gets the pop after a felt plugging in ac shore power

 

[Bryon Carpender]

Now I’m thinking it a feed back we
Tried plugging and unplugging ac no noise in that compartment no noise in the side compartments not in the tv bay or the engine compartment seems to to be coming from the passenger side speaker top right front

This other device is a tyco relay next to the battery relay

Also I had the couch battery switch off with ac plugging in and out and still pops with the couch battery on

 

[Bryon Carpender]

black wire not ground is a 22awg 4 conductor power gear wire lucky again.
Have to cut the sheeting but I think it ok

So disconnected the right speaker no limits to the sealing tape . So it’s feedback now the pop comes from the left rear speaker

At least it’s not an ac safety issues as much someplace Their is dcTo the speakers

Trading up problems

 

[Bryon Carpender]

The tyco relay is in the 2nd picture above readily available 50 bucks this an spat 260 amps those blades are relay contacts hence the insulated studs

Well bummer another project someplace a wire is pinched to the speaker wires and it goes to both speakers

 

[Morich]

Okay, always good to see actual facts and compare to drawings. This seems to mostly fit as expected, other than the ground for the solenoid is on right mounting screw instead of left! NOT bad!
If we compare the drawing above, most of the parts and wires fit as shown.

A help I had not mentioned yet is the way Winnebago stamps ID on their smaller wires.
Down at bottom left corner of various drawings that give a link to a Wire ID chart.
That link get you to this list where we can look up any drawing or wire ID to find where it comes from/goes to.

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/electrical_guide.pdf

Not the handiest as they did not make it searchable for ease of moving around without a week of scrolling but it has good info once we find it?
For instance GJ gets us this?

So we should find a yellow 12 or 16 gauge wire from the battery disconnect that stays hot and feeds various safety items!

See where I marked one of the ID I could spot on the pictures and I marked in green? If we go to the list, we can find this info!

Only on smaller wires and not always the handy thing but better than crawling and tracing when it works!

But that is where I may be spotting trouble-- or not?
Is that 15amp fuse that seems to just be hanging, part of the wire which melted down? Or just in my mind?
what I'm thinking it that fuse is not part of the OEM wiring and that leaves us guessing at wild cards that have been added to the RV. Thought is that there are empty slots on that fuse panel, so why was the fuse left hanging and not on the panel where it could be handy as well as found without taking the panel out?

Am I just looking for trouble or are you following a haywire type guy? If it is part of the wire that melted, maybe they should have done a better job of keeping it out of trouble and tied it down a bit?

 

[Bryon Carpender]

This looks to be mostly oem

That black wire is for the levelers? Assuming as it says power gear 4 conductor 22awg think their is only pin hole scrape it appears to be covered with rtv once it was away from solenoid definitely was in contact (we had an issue last trip with the levers not leveling) Humm

Once I confirmed not the issue I left it alone the fuse is 15 amp and is intact
Will check it for id this am

It appears the tyco 260 amp relay feeds the solenoid or vice a versa

So my My new assumption is the burnt shore power wiring goes to the converter directly and
The separate generator plug is a plug in

So maybe the ground neutral wire is in contact with the common ground DC of the frame and the shore power neutral which was toasted is bare someplace on the way to the power converter (this maybe a ghost run again but in my overthinking) makes as much sense

Major pita to pull and check hate to do an isolation test I have an old hypot tester but I have to open that box again and run a lead after running a separate ground and disconnect the positive from the batteries as I need the grounds intact
Another overthinking moment

Open to suggestions?

 

[Bryon Carpender]

Only close up of the fuse

 

[Morich]

This gets into the part where each company builds a part and then the RV is put togehter from parts built by others!
So what you are likely to be seeing is wiring that is part of the levelers and we d=get little to none of the info we need for them. A bit of the story that Winnebago buys a truck body and then adds parts to it and one of those added parts is the levelers and we get only very little idea of wiring for them from Winnebago!
It can get awkward as we have to chase a different builder if we need to get very far into things like the levelers.
On the big red cable, the one cable comes pretty directly from the coach batteries to the left side of the disconnect relay. That is just used as a mid point to connect to a second short cable to get coach power on to the solenoid, But if the disconnect really is closed, that coach power is then connected on to the right through that relay and feeds much of the RV including the generator starting.
This is the 110AC drawing for your RV.
But the idea is that some RV have an automatic transfer switch that connects the shore power cord if power is there or the generator wiring if it is running and no shore power. But in many RV, it is like what you have and I call it a "manual transfer" as we need to plug into shore power or the generator output. I tend to always plug into the generator box, as that means I can stop along the road and start the generator for a quick lunch without having to go out to move the plug! Plugged into the generator box, I can do it in the middle of the night without trekking around in the dark! One way to know where I left the plug??

https://www.winnebago.com/Files/Files/Winnebago/Resources/Diagram/2018/000152864.pdf

One big difference in RV versus house wiring is that the neutral doesn't always go back tot he breaker box in RV.
In both house and RV, both the white neutral and the bare ground wires all go to ground.
In house wiring we take it back to one central location at the breaker box.
But in automotive/RV work we have the frame to use as great big wire that is handy to find all over the vehicle and they may just go to it at lots of different points.
Just a bit different thinking/planning but the operation is close to the same. Power out on the hot wire to an item and then back to ground on the neutral. RV is any point on the frame and house usually goes fully back tot he breaker box. Then the bare ground wire is connected to most metal items like the stove and frig as a safety to be a better path to ground than if we find power getting to the metal of the stove and WE make the path to ground and carry too much current to kill!
Normally the hot and neural carry the load and the ground is just there in case we need it when one of the other two go bad!
That set of breakers where you are working is one that is hard to figure at times and not drawn to be really clear, as it acts as a main breaker for other panels and has both chassis and coach items on it.
They give us a front drawing here that is slanted to make it a bit harder to follow the breaker to the holes where they are mounted and the labels.
This drawing sheet 1 for the front!

But if we need the circuit or wire ID and to figure what goes through here, we need to go down to bottom of sheet 2 to look at the back. When viewed from the back we have to mentally turn things around and count the other direction?

There is a lot of info there but it is a trek to get it to make sense at times.
One basic thing to keep in mind when looking at fuses or breaker is that big like 55 amp are likely to be the mains and feed other smaller breakers/fuses.

It's a real trek at times, but it keeps me busy and off the street!

 

[kamphiker2]

Your digging through the diagrams and learning how the circuits are connected. BRAVO ! Your catching issues that could be catastrophic if not fixed. That said, On my current Vista 27P (2020) the OEM Solenoid 008188-01 (Trombetta is the mfg) same as on your 2019 failed. This same one has failed on my previous Winnie MH's over time. I replace them with the a much better 100% service rated also by trombetta but in the "Bear" family (See attached OEM in Hand and Replacement in Background). Now, the "Popping" sound, I get a Popping sound when I plug into shore power and it is from relays in the Air conditioner (s) control units within the AC's housing. My 2020 27P is 50 amps with automatic changeover but the Roof AC's should be the same even though a 30 amp Vista only has 1 AC unit. check to see if the popping is coming from the ceiling area at the AC intake vent.

 

[Bryon Carpender]

That’s very interesting, removed the right outside front speaker and it changed to the rear left

Certainly worth checking that idea out

I put everything back in the compartment
The fuse is tied to the wiring

I addd a tie to the power gear wires to the bundle keeping it away from the solenoid

 

[Bryon Carpender]

Looks like LJ and BJ in the yellow fuse wires also front connector of relay shown