Brush Holder

Check movement of brush in brush holder. If brush movement within brush holder is sluggish, check brush holder for distortion and sliding faces for contamination.
Clean or correct as necessary.
Check for continuity across insulated brush holder (positive side) and grounded brush holder (negative side).
If continuity exists, brush holder is grounded due to defective insulation and should be replaced.

Fig 1: Identifying Brush Holder
Courtesy of SUZUKI OF AMERICA CORP.