Update:

Ok, I got the battery verified as good to go, and got a full charge on it. Brought it home, popped it in the Disco, and it turned right over.

Good News: None, really.
Bad News: It's a short.

Went to Radio-shack and got a cheep'o multimeter, and discovered I was pulling half an amp in a steady state.

Started isolating circuits, and only got done with the gross scale on the fuses in the engine compartment. This is how it broke down:

MF 1: 1.31mA
MF 2: 0mA
MF 3: 12.2mA
MF 4: 17mA
F 1: 0mA
F 2: 0mA
F 3: .33mA

MF 5: 0mA
MF 6: 0mA
F 4: 10.5mA
F 5: 0mA
F 6: 0mA
F 7: 0mA

I don't know why the sum isn't the .5A that I saw with all the fuses installed. I might be reading the multimeter incorrectly. The next step is to pull the fuses on each of the subsidiaries in the Fascia Box, but I won't be able to get to that until next weekend. The battery has the negative terminal disconnected right now.

Is there a book somewhere that says what the total load (a component draw would be even better) should be on the battery while parked?

 

Look up Rover Chris and send him a PM, he is a 12v electrician.

 

I replied to your PM then found this thread. those parasitic draw readings are probably about what they should be. ideally any parasitic draw of less than 50 mA is normal and won't prevent the vehicle from starting for at least a few months of constant drain. sounds to me that maybe a relay got stuck or possibly a loose or pinched wire that has since been moved and is no longer causing a large drain could be at fault. do you still have a problem, or does it seem to be resolved?

also on a side note, places that test batteries don't usually test them right, they just charge them up full and see if they hold the charge for an hour or so, if the battery is completely shot this method will usually work good but it is not always accurate if the battery is starting to fail.

 

How to Find a Parasitic Battery Drain - wikiHow

If your using an inexpensive meter (which is fine) and using the 10 amp scale and had .5A draw then that is 500mA and that is a concerning draw. Like Rover Chris said, 50mA is fine. Just remember that 1000mA is = to 1 amp. Please disregard this if you already know this. Sorry I don't know how much you know.

 

here are some thoughts that may help you with a parasitic draw - leaving headlights on will draw roughly 10 - 20 amps maybe 30 with all the side, rear and dash lights on ( this will kill the battery in a couple hours), leaving a glove box light on will draw just under 1/2 an amp (may kill a battery over an evening and a night), the parasitic drain from the memory in your clock, radio, alarm, or any of the ecu's should be less than a few (2 or 3) mA each. the alarm uses a little to power the LED but not much. so really I would think under 30mA is what it should be. a standard 9V battery (or even a couple AA's) should be able to support that for at least a few months with no problem.

 

Chris, I am so glad that you are "down" but not "out".

 

is there any chance that your dome lights were still "dimming" when you checked and got the .5 amps? I had an Acura come in once that was draining the battery every other night, and it was drawing .5 amps, turns out it was the cassette player (yeah, this was a while back) trying to eject the tape when turning the key off. It was broken and always thought the tape was still in. A lot of cars do some "shutdown" house keeping that can cause them to draw a little more power than normal when you first shut them down. I just googled something that said some fords will draw .8 amps for about 20 minutes after turning everything off. I'm guessing it's for things like powering the computers for being able to roll windows up or down and reseting climate control doors.

 

No, the doors and everything had been shut for at least a half hour prior to taking the .5A reading.

I've got to go to the Land Rover dealership to hunt down some inserts for my truck's overhead map holder while I am here in Seattle.

For some reason, I can't find anything (new or used) about the map holder in the overhead. I can find the sunroof ecu, all the switches, but no plastic mold or screw inserts that the mold is fastened to.

When I get back to Idaho, I'll see about taking some better readings.

It's interesting that the cassette deck was mentioned. As I was taking readings on one fuse, I heard this component cycling over and over as I attached the probes to the ground on the battery.

It turns out that it was the 6-CD Changer. I wasn't even aware that it was installed, and had assumed that it had been removed because I'd never seen it.

 

I have learned that radios are a common power drain, usually it is because they are hooked up wrong

 

On mine, the original cd player under the driver's seat had shorted when a PO took it off-road and did some fording with it. He had it replaced but they did a poor job. I have removed all carpeting, the CD deck, the dash mounted radio, rear amp and speakers, headliner is completely out but I remounted the map holders and visors.

Had to have the visors and those lighted mirrors back in there. Anyway, the factory wiring is horrendous under the front carpets. Has in line splices, If you had a lot of water invasion, did carpets get soaked? Those pads hold gallons of water and often rust out the floor panels. Look under your carpets if you have not already. LR's have a history of wierd problems associated with bad splices, corrosion especially at grounds. Particularly the battery and starter grounds to the frame will give you fits my friend.