Another Starting Battery/Van electric issue
So a few times on our last trip I would hear a sound while driving that sounded like the automatic locks were firing, like the zapper had been pressed- but it hadn't. One night, while book docking, we heard the locks fire a number of times. For the rest of the trip, we'd occasionally hear the locks firing.
We got home uneventfully, and emptied and parked the van, not plugged into anything. Tonight, when we went to start it, the starting batteries were dead as a doornail!. The zapper wouldn't even open the locks. I plugged in the little voltmeter, and got no reading on the LCD or on the lights whatsoever- dead dead dead. (I checked the house battery- still the original 4d AGM from 9 years ago- and it was at 12.4).
Hooked up the charger, and as soon as I hooked it up, I heard the locks firing again. The charger read very low voltage, but within a few minutes it was charging up to the 12 volt range. The starter fired up, but not w/ enough juice to turn the diesel over. I've left the charger hooked up overnight, to bring the starting batteries up to normal.
The starting batteries are 3 years old, and I haven't had any issues with them. I can only hook up the charger to the under hood charging battery, but the other one (under the van) was replaced identically at the same time.
In the past, the van's been hooked to shore power when parked, and I haven't had any issues w/ starting it when not run for a few weeks, even in the dead of winter.
Is the collective wisdom thinking short somewhere? fuse issue? or another unusual drain?
My thought is to take it in to the dealer tomorrow to get it checked. Any other ideas?
03 7.3 PSD