My mirrors for my 80 320i hove stopped working electrically. What could be the problem?

The most likely culprit is the electrical wires where they pass from the door to the frame of the car. The insulation and maybe even the copper conductors have cracked due to the flexing. Solution: take off the door panels, disconnect the wires and replace entirely or splice in new sections of wire to cover the vulnerable door-frame area. I used crimp splice connectors that were made with shrink-wrap plastic cover. After the wires are spliced and crimped solidly, a match causes the plastic cover to contract and waterproof the joint. (Note, the above assumes that you have checked fuses and obvious things like that.)