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Alternator Fr Terminal Signal

  1. Connect system checker harness between ECU and connector. Connect voltmeter positive probe to terminal B14 (White/Red wire) and negative probe to terminal A18 (Black/Red wire). Start engine. Turn headlights on and off.
  2. Voltage should drop and then raise 0-5 volts as headlights are turned on and off. If voltage does not change, stop engine. Check for continuity in White/Red wire (Blue wire on CRX Si) between alternator and ECU. If there is continuity, check for faulty alternator and/or voltage regulator. If no continuity, check for open circuit in harness.
  3. Test FR terminal diode. Diode is faulty if continuity or no continuity exists in both directions between F and FR terminals of voltage regulator.
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