Re: 88 Dodge Xplorer Electrical Problem
I'll assume you've checked all lights (sure they're off when the van sits idle, and not drawing current), and CO/propane detectors, and any other 12V accessories, and disabled them by disconnecting their wiring or using a coach battery disable/disconnect switch if one exists? I'm guessing (because I'm not familiar with the Xplorer wiring and equipment) that the battery isolator/separator is wired wrong, or has a failed diode or two. Do you know where it is, and can you get a wiring diagram for it from somewhere, maybe from the manufacturer, or online? If you can find a procedure, test it for proper directional flow, and make sure it is inhibiting and allowing flow in the correct directions. It sounds like the coach accessories and appliances/lights (12V draw) are pulling down the engine battery. You might also check with a multimeter whether all batteries are getting 14.4 V when the engine is running (verify the alternator is charging everything).
I had a failed isolator, bad diode, and it would pull down the engine battery when the van sat idle with the coach batteries enabled for a few days. Replaced the isolator, problem solved.
It's not a sprint(er) (unless you make it one), it's (hopefully) a marathon.
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