My '94 NA 850 has all the dash lights coming on. If I rev the car, they usually go off, but not always. The belt is tight, doesn't appear to be slipping or have damage, or fluid contamination. The car has well over 400K miles and still has the original alternator. I changed the brushes once, years ago, so I'm suspecting the alt is the issue. My question: I was going to try a new set of brushes, but should I just go for a whole new/refurbished unit?

thanks
mark

Any car that I every owned with bosch electrics in was always reliable and the components really lasted. The bosch rotors and brake pads are another story...