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Power Circuits (4.0L)

  1. Using a voltmeter, check for battery voltage between ECU terminal B-7 and ground. See Fig 1. If battery voltage is not present, check diagnostic connector No. 1 terminal No. 5 (D1-5) for proper seating. See Fig 1. If connector is okay, check for an open in Red wire between ECU and D1-5, and between D1-5 and battery.
    Fig 1: 4.0L ECU Connector Diagram
    G90I15881Courtesy of CHRYSLER MOTORS.
  2. Turn ignition switch to the ON position. Using a voltmeter, check for battery voltage between ECU terminal B-8 and ground. See Fig 1. If battery voltage is not present, check for an open in Yellow wire between ignition switch and terminal B-8 of ECU, or check for a defective ignition switch.
  3. Connect a voltmeter between ground and ECU terminal C-3. See Fig 1. Turn ignition switch to the START position. Battery voltage should be present between control unit terminal C-3 and ground ONLY when ignition switch is in the START position. If voltage is not present, check for an open in Green wire between ECU terminal C-3 and start relay, or check for a defective start relay or ignition switch.