Mystery connections on used I5

[lyhoftom]

Just picked up big blue (2018 30FW) this weekend and we couldn't be more excited to take her on the maiden voyage in a few weeks. While in the process of cross loading from the old RV, baselining maintenance items, and generally trying to eyeball everything, I came across what appeared to be a 12v heavy gauge cable just lying in the pile of wires next to the inverter. Thankfully it wasn't hot but traces all the way to the back where the shore power connects. I rang it out and it tones to the ground lug on the shore power plug, which is weird for a red cable. Any ideas?? There is also a vacant auto circuit breaker in the same bay with only the hot side connection...also weird but might be an add-on. Finally, I haven't downloaded all the manuals, but ideas what this fuse bank is for? Any ideas would be greatly appreciated for any of these, see below pics.
Thanks all, you have already been a wealth of info and helped me spend more money today on tires Tom

[NavyLCDR]

The extra lug in the top photo looks like a black wire with red heat shrink. I would first do a voltage check between it and ground and if volts is zero, then do a continuity check. If it has continuity between the lug and ground, then I would connect it to a grounding point.

Can't help you on the other questions.

[Desert Boat]

Reading out to ground is not conclusive, as you could be reading through a motor or control circuit. It could still be a positive supply wire.

Thoughts for things that might be on an auto-reset breaker - macerator toilet, entry stairs, macerator discharge pump, levelers. May be others. Do all of these work?

Problem with an older coach - you never know what sort of shade-tree mechanic work has happened on the electrical system. Maybe the auto reset failed, the mechanic could not figure it out, and jury-rigged power from somewhere else.

My recommendation - tape it off so it is safe until you come across something that is not working. The alternative is to try and follow it through wiring bundles to the load, which can be challenging.

[van_fl]

2019 Isata 5 fw fuses in electronic bay

10A Chassis battery sense. Used for Precision plex to display chassis battery voltage reading.

5A House battery sense. Used for auto gen start and Bird house battery voltage sense.

20A Entry step main chassis battery power.

7.5A Entry step ignition override.

[lyhoftom]

Thanks to everyone so far! The heavy gauge wire is definitely red, that black that you see is the electrical tape securing the wire loom, the wire is red all the way to the back where it disappears into the foam by the shore connection. I already taped it off, just wanted to see if there was an ah-ha here before continuing to investigate. Agree that going to ground isn't overly helpful, but sure better than 12V or worse unfused 12V! Everything that I've tried works (steps, level, etc), not sure if it's got a macerator toilet as that would be a new deal for me, but will check. Flushing sounds normal, but what do I know! I also haven't sorted that pile of wires to see if there's another exposed connector hidden gem in there that is sized to match the breaker. It doesn't seem to be a failed one deleted, as it's still has a hot connection on the bottom and the outgoing is also hot...mystery continues. There are some add-ons such as the disco LED lights around the lower rail all the way around the coach, so that increases the random factor a bit. I guess I will be hosting the parties tho! Thanks van_fl for the fuse deets!!

[van_fl]

I have the wiring dwg as a pdf . However I can’t seem to post it here. Send me your e-mail and I will send all dwgs that I have. I have a 2019 but should be mostly correct.

[BLT4SPD]

Originally Posted by lyhoftom

Just picked up big blue (2018 30FW) this weekend and we couldn't be more excited to take her on the maiden voyage in a few weeks. While in the process of cross loading from the old RV, baselining maintenance items, and generally trying to eyeball everything, I came across what appeared to be a 12v heavy gauge cable just lying in the pile of wires next to the inverter. Thankfully it wasn't hot but traces all the way to the back where the shore power connects. I rang it out and it tones to the ground lug on the shore power plug, which is weird for a red cable. Any ideas?? There is also a vacant auto circuit breaker in the same bay with only the hot side connection...also weird but might be an add-on. Finally, I haven't downloaded all the manuals, but ideas what this fuse bank is for? Any ideas would be greatly appreciated for any of these, see below pics.
Thanks all, you have already been a wealth of info and helped me spend more money today on tires TomAttachment 283449Attachment 283450Attachment 283451

I *THINK* that those auto-reset breakers and the "extra" wire are for the slide controllers. The factory produces one wiring loom (I think) for the Isata 5. Since you have a 30FW with a single slide and the other floor plans at the time would have had two slides, that breaker and that wire simply would not have been used.

[bclemens]

From electrical engineer....
"See attached for fuse and circuit breaker assignments. The one breaker not used is a macerator toilet prep. Not sure on the large cable, looks like the 4/2ga that would feed the multiplex above the entrance door or the jacks but it doesn’t sound like those are issues.

[lyhoftom]

Thanks again everybody 2 out of 3 is great progress in just a day, I will see if I can sort the 4/2 this weekend and report back