2000 E350 V10 - The auxiliary battery charges all the interior lights, among other things... Well, they've dimmed out over the course of 2-3 days and now the vehicle is completely dark inside. Battery seems fine, but must not be charging (at all).

Ideas anyone? I am hoping to find some sort of auxiliary battery charging system diagram or something showing where the relays and such are, so I can get in there and find the fix.

I have no clue where to start... ANY help would be amazing. Thanks!

 

All I can find at autozone is the single battery system with the single alternator shown here.
http://www.autozone.com/autozone/rep...All%20Gasoline)

If you look at the diagram, there is a "battery junction box". This is the underhood fuse box, and if you notice, they have a large fuse in there for the regular battery. I would check and see if you have another large fuse in there for the aux battery. And also follow the aux battery wiring and look for any open fusible links.

If I get time, I have the factory manual for your model at home, and I will see if they have the aux battery diagrams.

 

This is definitely a good jumping off point. Thank you so much.

I read something yesterday that there is an "Aux Battery Relay located on the base of the Aux Battery tray." When I get home this evening I'm going to have to pull it into my barn (where I have a pit) and check that out too.

Beforehand though, your suggestion allows me to go out to the parking lot here at work during business hours and if the 60A fuse is toasted, get it changed out before having to disassemble that "amazingly inconvenient" second battery housing.

With fingers crossed, I will give it a look-see and let you know what I find.

Please let me know if you find more info out... The web has been pretty dry on info regarding this.

Thanks Again!

 

I had trouble finding the aux battery on my DVD at home. When I finally did find it, I then knew where to look on the autozone site. Here's a link. If you keep hunting around in the power distribution diagrams, you may find more.

http://www.autozone.com/autozone/rep...e%2005%20(2000)

 

Awesome! Thanks again so much. Yesterday I discerned that the 60A fuse was fine as were any dash-side fuses... This gives me exactly the "fuel" necessary to go further.

I'm pulling it ALL apart this weekend. I WILL find it dammit!!!!

Hopefully, I will be able to post the resolution to it all come Monday!

Thank you, thank you, thank you!

 

OK, my weekend endeavors were fruitless. After tracing the lines and disassembling the second battery housing (PIYA!!!) I at least know that the second battery is now completely dead. But I do not know how it happened or what drained it. (it was only a year old - from the dealership)

I did discover that what ever it was, when I put our battery tester / charger on the unit to figure it out... There was a loud pop and sizzle followed by a lovely plumb of smoke from my, now DEAD, battery charger (RIP).

Completely baffled and no closer to figuring it out, I gave up until I can replace the battery and try again.

Solenoid? Relay? I dunno. Does anyone know how to test those buggers?

Sigh.............