Hi, I need some help diagnosing a serious electrical problem with our
car, a 1990 320iSE. For a couple of weeks, the headlamps and dash
lights have been flickering intermittently whilst driving, and last
night the flickering got worse, and the blower motor started slowing
and revving repeatedly. The fluctuations aren't particularly related to
revs. As i pulled into the car park (about 9 miles later), the engine
cut out, and there wasn't enough power in the battery to turn the
starter, so it had obviously been draining rather than charging. Had to
get a recovery van out, who leant us a power pack to get home on (still
flickering). He connected a multimeter across the battery with the
engine running and reported that it was charging to some extent, but
that the voltage was jumping around all over the place.

First thought was that the alternator/voltage regulator must be dead,
but I also fear that bad wiring somewhere could be responsible? Before
I start dismantling things and buying expensive parts is there anything
else I should test or consider?

Thanks!