Rectifier Short or Grounded and Stator Grounded Test

Diode Trio Test:

Alternator W/Integral Regulator Rectifier Short Or Grounded & Stator Grounded Test:

1. Using a suitable ohmmeter, connect one probe to alternator BAT (B+) terminal and the other probe to the STA terminal (rear blade terminal). Then, reverse the ohmmeter probes and repeat the test.
- A reading of about 6.5 ohms should be obtained in one direction and no needle movement with the probes reversed.
- A reading in both directions indicates a bad positive diode, a grounded positive diode plate or a grounded BAT terminal.
2. Perform the same test using the STA and GND (ground) terminals of the alternator.
- A reading in both directions indicates either a bad negative diode, a grounded stator winding, a grounded stator terminal, a grounded positive diode plate, or a grounded BAT terminal.
- Infinite readings (no needle movement) in all four probe positions in the proceeding tests indicates an open STA terminal lead connection inside the alternator.