radiator fan

98 escort zx2. the radiator fan seems to have stopped working. Does the whole fan need to be replaced or just a certain part of it?

brushes in the motor?? is there power going to the motor when hot? relay that feeds power to motor? I got a whole fan unit from the junk yard and took the brushes out for my fan unit. The junker was a different unit but same fan. Works now ok.