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Alternator Fr Terminal Signal

  1. Plug 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 zero to 5 volts as headlights are turned on and off. If voltage does not change, turn off engine. Check for continuity in White/Red wire (Blue wire on CRX Si) between alternator and ECU. If continuity is present, check for faulty alternator and/or voltage regulator.
  3. If there is no continuity, check for open circuit in harness. 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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