: Someone mentioned the diodes within the alternator as having back feed. The electricity could be flowing back to the gauges.

I had an alternator problem with my 83'320i and had the same thing happen. Now one of your problems could be that your alternator ground is bad which makes the light stay on. You would also have to be careful with this because this may burn out your alternator in which case you would have to buy a new one or do what I did and got to a junk yard and pick up one. Alternator work can be frustrating but your problem sounds like a bad ground. you will have to check the condition of the strap that is underneath the alternator because that is where your alternator is grounded to. The best way to find out if it is a faulty ground is to keep the old ground connection and then make a new ground wire and ground it to something else. hope this helps.

: Could this be the cause??? I'm having to disconnect the battery each time as not to drain it.

: Thanks,
: Martin