Help

I have had several problems with my mini all involving electrics. The
problem at the moment is that the alternator is not charging. I had the same
problem a week or so back and took the alternator in for testing and it
proved to be faulty. I bought a new alternator and fitted it after the first
journey with this one the charging light came on as before and now won't go
out. I've checked the output and it is not putting out anything more than
the 12volts from the battery. I've previously replaced the earth strap from
the engine. Could anything cause a new alternator to fail so quickly, or
have I just bought a dud? I have been checking the circuits tonight and have
taken apart and remade the connections at the starter motor. Interestingly
and possibly connected I have found that with the battery disconnected and
using a meter to check resistance I can get a circuit between the live and
earth wires (ignition turned off and all doors shut). this circuit is
present until I disconnect the fuse that feeds the indicators and the
interior light. I should say that the car is a 1993 spi cooper fitted with
an alarm and touch key enabled immobiliser. The resistance drops if you open
the doors and I have disconnected and checked the door switches just in
case. I have also disconnected the feed to each of the indicators in turn
which had no effect. I don't have any circuit diagrams of the alarm circuits
in the mini.

I would like to know the following could an electrical fault cause an
alternator to fail like this, if so what sort of fault? Is it normal to have
a circuit between live and earth with nothing switched on (my battery does
go flat if the car is left for a couple of weeks, even without the alarm
switched on)?

I can replace the alternator under warrantee but I don't want to do this yet
if something is causing the failures. All help much appreciated.

Kevin