First guess?
I am used to having a relay that opens/closes the path to "most" of the 12VDc users. That relay is controlled by the battery disconnect switch at the door. Safety item did not go through this relay but are left on full time!
One small check is to look at the CO and propane detectors for a small green LED still lit!
If that is on and the rest of the 12VDC coach items dead, it says you do not have a battery or charge problem but a problem getting that power through the fuses and to what needs it!
I assume that switch is left on? That switch moves the relay and that is likely the thump you are expecting?
But the ones I have looked at have a special relay that is called a "latching relay". when we press the switch it uses power to mve the relay but we don't want it to use battery full time so the relay has a magnetic gizmo to "latch" it in whichever last position we move it to.
Verify that the switch youe push seems to bounce back when released, rather than a simple flip to one side or the other?
Tricky questin time! Do you get the thump and is it possbile to find where that thump is coming from? I aaaam thinking the thump is the relay moving, but there may be aproblem with the magnet not holding itto the closed side??? Maybe it stays and most things get power but for some reason the magnet is not holding full time???
they no longer give us the good schematics to say that is still the way they do it, but they do tend to be slow to change, so guessing it is still that way!
Not finding parts or drawings to back that idea, though!
If you try pressing and holding the disconnect switch to connect side, do the lights and power come on and stay if you hold it manually?
Or is the noise coming from near the rear on driver's side? This drawing shows where it looks like under the bed and possibly behind the 12VDc fuse panel?
If it gets ionto this area where the data links go to modules, I have to say I'm out of ideas to go deeper.
No tools to trace data or even knw which module to start on!
Theory says we might get in there and wiggle some wires but that is way, way out in the weeds with little hope!
