Stator Grounded Test
- Perform test before alternator disassembly. Adjust ohmmeter to x1 scale. Place ohmmeter lead on alternator "BAT" blade terminal. Place remaining lead on the "STA" terminal and note reading. See Fig 1
. Reverse ohmmeter leads and note reading.
- Reading should not show needle movement in one direction. This indicates rectifier diodes are being checked in reverse current direction. Low reading of approximately 6.5 ohms with leads reversed indicates that positive diodes are being checked in forward current direction.
- Readings in both directions indicates defective positive diode or shorted radio suppression capacitor. Radio suppression capacitor is built into the rectifier assembly.
- Place ohmmeter lead on "STA" blade terminal and remaining lead on alternator housing. Reading in both directions indicates a grounded stator winding, defective negative diode, a grounded stator lead wire or shorted radio suppression capacitor.
- Check for bad connection in rectifier if no reading is obtained in either direction or excessive resistance is obtained.
Courtesy of FORD MOTOR CO.