Ford — Diode Tests - On Bench
Testing & diagnosis · Rectifier assembly
From a Ford service manual — check it applies to your exact model before use.
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Before you start
- Always use a recommended diode tester to check diodes
Procedure
- Disassemble the alternator and disconnect the rectifier assembly from the stator.
- Contact one probe to the diode plate and each of the three stator lead terminals with the other probe.
- Reverse the probes and repeat the test.
- Test the other set of diodes the same way; on 61-ampere alternators test two additional diodes.
Tools required
- Rotunda ARE 27-42 ohmmeter (multiply-by knob set at 10) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Low reading of approximately 60 ohms in one direction and infinite reading with probes reversed
Source: Ford service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.