K 1500 Truck 4WD V6-4.3L VIN W (1997)
Except as stated, make the following tests with an ohmmeter on the low range scale.
Rotor Field Winding Tests
Regulator Connections
The rotor may be tested electrically with a self-powered test lamp or an ohmmeter.
Open Winding Test
To test for opens, connect the test lamp or ohmmeter to each slip ring. If the lamp fails to light, or if the ohmmeter reading is high (infinite), the winding
is open. Replace the rotor.
Grounded Winding Test
Connect a test lamp or ohmmeter from one slip ring to the shaft. If the lamp lights, or if the reading is low, the rotor winding is grounded. Replace the
rotor.
Short Circuit or Resistance Test
Test the winding for short circuits or excessive resistance by connecting a battery and ammeter in series with the edge of the two slip rings. Note the
ammeter reading and refer to "Generator Specifications,". An ammeter reading above the specified value indicates shorted windings.
An alternate method is to check the resistance of the field by connecting an ohmmeter to the two slip rings. If the resistance reading is above the
specified value, the winding has excessive resistance; if it is below the specified value, the winding is shorted. The specified resistance value can be
determined by dividing the voltage by the current.
Remember that the winding resistance and ammeter readings will vary slightly with winding temperature. If the rotor is not defective, but the generator
fails to supply rated output, the problem is in the rectifier bridge, stator, or regulator.
If the rotor fails any of the above checks, replace it.
Stator Test
Testing The Starter For Grounds
Test the stator with a self-powered test lamp or an ohmmeter. If the ohmmeter reads low, or if the lamp lights when connected from any stator lead to
bare metal on the stator frame, the stator is grounded.
An ohmmeter cannot be used to test the delta stator for shorts or opens. Noticeable discoloration on the assembly usually indicates a problem in the
stator windings.
