First question I'm going to ask is it a genuine Eurovox unit, if not don't waste your time.
The way to test them is put a negative power supply of 12 volts to the body of the antenna and then the positive to either the Red or white, one is for up the other one is for down. I have rebuilt hundreds of these over the years and sent them all over the country, but it seems no one want to pay a sensible and fair price anymore for a fully rebuilt unit so I stopped doing it and let them buy inferior Aerpro units.