Bronco L6-300 4.9L VIN Y 1-bbl (1983)
Rectifier Diode / Bridge: Technical Service Bulletins
Alternator - Rectifier Bench Test Procedure
Article No. 84-3-5
ALTERNATOR - RECTIFIER BENCH TEST PROCEDURE
FORD ALL
LINCOLN-MERCURY ALL
LIGHT TRUCKS ALL
MEDIUM/HEAVY TRUCKS ALL
During a recent dealer survey, it was discovered that some technicians are using digital meters for alternator testing, despite specific instructions in the
Shop Manual to the contrary. The digital meters cannot be used for checking rectifier assemblies or diodes in the alternator. This may explain a portion
of non-defective rectifiers returned under warranty.
Alternator Rectifier Testing Information
The use of digital meters when bench testing an alternator rectifier assembly can cause misdiagnosis. It is recommended in the Shop Manual (Section 31)
that a Rotunda Meter Model #059-00003, or equivalent, be used. Equivalent test meters must be of the "analog" type, not digital. A digital meter could
only be used if it has a diode checking function. However, the readings should be compared with those of a new part to confirm the results.
If the rectifier is found to be okay, check for possible pinched or grounded wires to the inside of the housing. Then reassemble the alternator with the
tested rectifier. The Shop Manual Charging System Diagnostic Procedure should be reviewed to confirm proper procedures were used. Remember to
first check for proper drive belt tension and proper wire connections at the alternator and voltage regulator.
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY"
