Open Field Or Short Circuit Test
- Use an ohmmeter, set knob at "X1" and calibrate ohmmeter. Contact regulator "A" blade terminal with one probe and the regulator "F" screw head with the other probe. Rotate alternator pulley. Reverse ohmmeter probes and repeat test.
- In one probe direction, ohmmeter reading should be between 2.2-100 ohms. Fluctuation may occur while pulley is turning. In the other probe direction, reading should fluctuate between 2.2-9 ohms.
- An infinite reading in one direction and approximately 9 ohms in the other, indicates an open brush lead, defective brushes or a loose regulator-to-brush holder attaching screw.
- An ohmmeter reading of less than 2.2 ohms in both directions indicates a shorted rotor or bad regulator. If ohmmeter reading is significantly over 9 ohms in both directions, a defective regulator or loose "F" terminal screw is indicated.
- Contact alternator rear housing with one ohmmeter probe and touch other probe to regulator "F" terminal. Reverse probes and repeat test. Ohmmeter reading should be infinite in one probe direction and about 9 ohms in the other.
- A reading less than infinite in both directions indicates a grounded brush lead or defective regulator. If reading is significantly over 9 ohms in both directions, a defective regulator or a bad terminal "A" connection is indicated.