Measure the brush length. Replace the brushes as a set if one more of the brush length is less than limit. Brush length: Standard: 15.5 mm (0.6102 in.) Limit: 10.5 mm (0.4134in.) Use a circuit tester to inspect the brush holder insulation. Touch one probe to the holder plate and the other probe to positive brush holder. There should be no continuity.

Use a circuit tester to inspect the magnetic switch continuity. Touch one probe to the S connector and the other probe to the magnetic switch body. There should be continuity. If there is no continuity, replace the magnetic switch assembly. Use a circuit tester to inspect the magnetic switch continuity. Touch one probe to the S connector and the other probe to the M connector. There should be continuity. If there is no continuity, replace the magnetic switch assembly. aaa