Alternator (FA20): Inspection

Inspection of light-emitting diode

Check the continuity between the light-emitting diode lead and terminal E or terminal B. Replace the rectifier if the continuity is not as shown in the table.

Fig 1: Checking Continuity Between Light-Emitting Diode Lead And Terminal (E)

Courtesy of SUBARU OF AMERICA, INC.

ANALOG TESTER SPECIFICATION

Tester lead		Conductor
- Lead	+ Lead	Conductor
E	P1, P2, P3, P4, P5, P6	ON
B	P1, P2, P3, P4, P5, P6	None
P1, P2, P3, P4, P5, P6	E	None
	B	ON

DIGITAL TESTER SPECIFICATION

Tester lead		Conductor
- Lead	+ Lead	Conductor
E	P1, P2, P3, P4, P5, P6	None
B		ON
P1, P2, P3, P4, P5, P6	E	ON
	B	None

CAUTION: Megger testers (used for measuring high voltage) or other equivalent measuring instruments may damage the light-emitting diode. Do not use such instruments for this test.

Brush check
1. Using a vernier caliper, measure the brush length.
  Standard length: 22.5 mm {0.885 in}
  
  Minimum length: 5.0 mm {0.196 in}
  
  Fig 2: Measuring Brush Length Using Vernier Caliper
  Courtesy of SUBARU OF AMERICA, INC.
  
  If the brush length is less than the minimum, replace the brush.
2. Check the brush spring for appropriate pressure. Insert the brush to the brush holder until its tip comes out from the brush holder by 2 mm (0.0787 in.). Then, use the spring pressure indicator to measure the brush spring pressure. Replace the brush spring if the pressure is 1.7 N (173 gf, 6.11 ozf) or less. The pressure of a new spring must be 4.1 - 5.3 N (418 - 540 gf, 14.75 - 19.06 ozf).

Fig 3: Measuring Brush Spring Pressure Using Spring Pressure Indicator

Courtesy of SUBARU OF AMERICA, INC.