To check the alternator on your Massey Ferguson 165, you will need a voltmeter or ammeter. Begin by removing the lower fan housing, which is the black circular panel. Then connect the meter’s positive lead to the positive terminal on the alternator and the negative lead to the negative terminal of the alternator. With the engine running, the meter should read between 13.5 and 14.5 volts. If the reading is lower than this, the alternator is faulty and needs replacing.