1990 Plymouth Laser Base, AutomaticFACTORY OEM SERVICE PROCEDURE

A/C Control Unit

  1. A/C switch is located above A/C-heater unit. See Fig 1 . Disconnect A/C control unti electrical connector. Turn ignition switch and A/C switch to the ON position. Set temperature control lever to MAX COOL and blower switch to HI.
    NOTE: Refer to Fig 2 during the following testing procedure.
  2. Using an ohmmeter, measure resistance on wire side of A/C control unit connector terminals No. 1 and 6. Also, measure resistance at terminals No. 1 and 6. Also, measure resistance at terminals No. 5 and 7. Ohmmeter should read 1350-1650 ohms at 77°F (25°C).
  3. Using a voltmeter, measure voltage on wire side of A/C control unit connector terminals No. 2 and 3. With A/C switch in the ON position, voltmeter should read approximately 12 volts. Turn A/C switch to the OFF position. Measure voltage at terminals No. 2 and 8. Voltmeter should read 0 volts.
  4. Using an ohmmeter, check continuity at terminals No. 3, 4, 8 and ground. Ohmmeter should indicate continuity.
  5. Using a voltmeter, measure voltage at terminals No. 9 and 3. With engine coolant temperature at 172°F (78°C), voltmeter should read 12 volts. With engine temperature at 185°F (85°C), check voltage at terminals No. 9 and 8. Voltmeter should read 0 volts.
  6. Turn ECONO swithc to ON position, measure voltage at terminals No. 10 and 3. Voltmeter should read 12 volts. Turn ECONO switch to OFF position. Measure voltage at terminals No. 10 and 8. Voltmeter should read 0 volts.
  7. If ohmmeter and voltmeter readings are within specification, replace A/C control unit.
    Fig 1: A/C Control Unit Location
    G90G06298Courtesy of DAIMLERCHRYSLER CORP.
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  • • You smell fuel, burning insulation, or see smoke.
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