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Home >> Ford >> 1990 >> Bronco II RWD, Standard, M5OD-R1 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Relay Checks >> Fuel Pump Relay Power Check
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Fuel Pump Relay Power Check

  1. Turn ignition on. Use voltmeter to measure voltage between ground and terminals "B" (Red) and "C" (Black/Yellow) or "A" (Yellow). See Figure . If voltage at each terminal is more than 10.5 volts, voltage supply is okay. Proceed to FUEL PUMP RELAY RESISTANCE CHECK  . If voltage reading is 10.5 volts or less, proceed to steps 2 and 3.
  2. If voltage at terminal "B" (Red) is less than 10.5 volts, repair fuel pump relay-to-EEC power relay circuit. If the voltage at terminal "C" (Black/Yellow) is less than 10.5 volts, check 30-amp fuse in power distribution box. If fuse is okay, repair Black/Yellow wire between power distribution box and fuel pump relay.
  3. If the voltage at terminal "A" (Yellow) is less than 10.5 volts, check circuit between fuel pump relay and Batt (+). Repair as necessary. If circuit is okay, perform QUICK TEST in TESTS W/CODES article.