I'm trying to diagnose a battery drain on my '94 disco (bought in Boston, USA, so it's a north american version) that's been draining the battery erratically for the last couple of weeks.

Pulling a battery cable and putting an ammeter in circuit shows I'm losing about 350 mA.

That sounded suspiciously like the "you need to change your batteries in the keyfob" symptom that I see on some other
forums, so I change the batteries. The drain goes away for a few seconds when I lock and unlock, but it's still there.

Back to pulling fuses. None of the in-body fuses change anything. Strange behavior; drain still goes away on lock/unlock - but only for five or ten seconds. Then the drain comes back.

So, I go to the under-hood fusebox, and start pulling fuses. What changes things? The alternator fuse!

A clampmeter (near the limits of it's resolution) shows that indeed, there's 350-or-so mA of drain on the big 100A alternator cable.

Pulling the push-on field wire did nothing to change the drain. It still cycles when I lock/unlock.

1) what could possibly go wrong in an alternator to cause 350 mA of battery drain - is this an alternator problem or something else that just reflects into something on the alternator?

2) Why would it go away when the keyfob lock/unlock cycles, but only for five or ten seconds?

If I could figure this out, I'd throw a new alternator in it and call it done, but how can the alternator and the lock/unlock remote interact this way. I'm worried that the undocumented nature of the kill circuit is going to make this really hard to diagnose. I'm the original owner (21 years and counting) so there's no Previous Owner to blame.

[[[ After writing the above.... I gave the alternator a couple love taps with a deadblow hammer (a well-used Snap-on one I found on the street! Not kidding! It was lying on the street! ]]] But it worked; the power drain immediately dropped to 20 mA and it's stable over multiple start/stop/lock/unlock cycles. And also it's still stable after a few more love taps. (not kidding, I'm just rapping on it; I honestly could punch it harder barefisted)

What the Heck????? Lucas and Sons.... at least it had respect for Snap-On.

Anybody have any ideas?

- Bill