Explorer 2WD V6-245 4.0L (1994)
Alternator: Testing and Inspection
Field Open or Short Circuit Test
Alternator W/Integral Regulator Field Open Or Short Circuit Test
1. Using a suitable ohmmeter, connect regulator A blade terminal with one probe and the regulator "F" terminal screw head with the other probe.
2. Spin the alternator pulley and note meter reading, then reverse probes and repeat step 1. In one probe direction ohmmeter reading should be
between 2.2 and 100 ohms and may fluctuate while pulley is turning. In the other direction, reading should fluctuate between 2.2 and
approximately 9 ohms.
3. An infinite reading (no meter movement) in one direction and approximately 9 ohms in the other, indicates an open brush lead, worn or stuck
brushes, faulty rotor or a loose regulator to brush holder attaching screw.
4. An ohmmeter reading less than 2.2 ohms in both directions indicates a shorted or faulty regulator.
5. An ohmmeter reading significantly over 9 ohms in both directions indicates a faulty regulator or loose "F" terminal screw.
6. Connect alternator rear housing with one ohmmeter probe and touch the other probe to the regulator "F" terminal. Reverse probes and repeat test.
Ohmmeter reading should be infinite in one probe direction and approximately 9 ohms in the other.
7. If ohmmeter reads less than infinite at either point, a grounded brush lead, grounded rotor or faulty regulator is indicated.
