To check armature for a grounded circuit, check continuity between commutator and armature coil core. See Fig 1. No continuity should exist. Replace armature if continuity exists.
To check for an open circuit, check continuity between individual brush segments at commutator end of armature. See Fig 1. Continuity should exist between each individual brush segment. Replace armature if no continuity exists on any brush segment.
Support armature in "V" blocks, with "V" block positioned at each bearing end of armature. Using a dial indicator, check armature runout at center of commutator and at end of armature. Replace armature if armature runout exceeds .004" (.10 mm).
Using caliper, measure commutator outside diameter at center of commutator. Replace armature if commutator outside diameter is not within specification. See STARTER SPECIFICATIONS .
Measure insulator depth between commutator segments. See Fig 2. Replace armature if insulator depth is not within specification.

Fig 1: Testing Armature For Grounded & Open Circuits

Courtesy of HYUNDAI MOTOR CO.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Armature Test