Make your own service light reset tool or buy it from Racing King.

If you want to keep your E34 for a very long time... there is no secret, either you bring it to the dealer or a reputable independent, or you perform all the work yourself... and most of the time, because you know and care for your car, the work you will do on your BMW will be of better quality. (Except if you are a sloppy mechanic...)

Easy :

If you plan on working on your car the secret is

BMW 5 Series (E34) Service Manual 1989-1995

Get it from Racing King