electrical issue with new roof overlay

[willy]

Help. had roof overlay recently installed,now no ceiling fans nor furnace will operate.
Breaker - marked frt furnace/ceiling fans trips as soon as 12 volt power is switched on.
02 Adventurer 32ft

[Morich]

Well, this could be tough----or it could be just a nasty timing thing to make you think the roof was the cause! Gremlins have ways to confuse us, so keep that in mind!

But tell us a bit more about the process for the roof overlay. Were new fasteners of some type driven into the Rv and where? Glued on? What are the odds of that process driving a fastener into wiring?

For starters, this is your 12VDc coach wiring drawings where the furnace, etc is shown and I do spot a "suspect" for checking but it does bring some questions:

https://www.winnebago.com/Files/File...ire_137067.pdf

You mention ceiling fan, is that the bath vent fan or something else as I see the bath vent fan connected. Are we speaking the same thing?

Sheet two has this info. There are three wires on the furnace shown at top left and it looks like wire "JB" is the battery, with "JM" being the ground going directly to the ground bus bar. Possible removing the Wire JM from the bus bar would clear the fuse blowing (short?) and tell you something?

Sheet 2 frame 2 (S2F2) shows these wires also go to the vent fan, so it may get into needing to disconnect these two items from the wiring to find if the short is in the wiring due to damage or if it just happened that one of those failed to give the new short you are seeing???

And the last snip does show these going to a breaker. The drawings are shown looking at the backside if I am correct, so does that fit what you are finding blown or tripped?

[willy]

I've read your reply. Couple of issues. If momentary switch is on and then removed I still have coach 12 volt power. Is that good??
Disconnect ed both powered ceiling fans.breaker still trips. It is marked JB.
I can't find ground bus bar
Thanks for helping.
PS have no idea if any screws were used to install this rubber overlay.ill visit with the installer this week cuzz I'm very frustrated

[Morich]

The momentary switch? Is that the battery disconnect switch, possibly near the door that is meant to turn coach power on or off?
Guessing that is what you mean and there is a small point that many miss on that switch as it controls a relay that is different than most relays. The switch is momentary and goes forward or back but goes back to center when released.
It is tricky because it moves a relay open or closed to turn power on or off and most relays use power to keep them in one position. But the relay this switch moves is called a "latching" relay as it uses power to move but then when we let go of the switch, the relay stays "latched" using a magnet inside the relay! That means when we use the switch to turn the coach power on, it only uses battery power long enough to do the job and then stops using battery and lets the magnet hold it. Makes the battery last longer when boondocking!
Look close at that switch and you may spot that it moves one way to engage the power but "bounces back" to the center and you can push it the other way to disengage the power! So you get lights on one way, center off, and lights off the other way!
That's good!!

I'll do a search on the drawings to see if it shows where the ground bar might be. The idea is that if there was a screw or nail, etc driven through a pair of wires to make contact between the ground and the power wires that makes a short circuit and will blow a breaker or fuse. So if we disconnected the ground wire and the breaker stopped tripping, it might tell us more that it was a wire problem, rather than some fan or light, etc giving the problem.
Just kind of a first test. Easier that trying to sort out where all there might be screws or nails used as they likely did cover it all with caulking or paint of some sort. I would have thought they would be more likely to use some adhesive but sometimes on houses they use metal strip around the edges.
Just going to be tough to spot the problem.

[Morich]

This drawing does show a couple ground bus bars, one on the passenger side just behind the door and the other on the drivers side.

I think that wire will be connected on the passenger side one! If you find that wire I marked as ground in the other drawings, it may stop the breaker from tripping and that could tell us something about where the problem is.

Click this drawing to get a better view on the computer.

But checking with the folks who did the roof may tell you more.
Good luck to you as it is a bad deal!