A/C control unit is located above A/C-heater unit. See Fig 1 . Disconnect A/C control unit electrical connector. Turn on ignition and A/C switch (Green light). Set temperature control lever to maximum cool and blower switch to high position.
Using an ohmmeter, measure resistance between terminals No. 1 and 6, and terminals No. 5 and 7 on wire side of A/C control unit connector. See Fig 2 . Ohmmeter should read 1350-1650 ohms at 77°F (25°C).
Using a voltmeter, measure voltage between terminals No. 2 and 3 on wire side of A/C control unit connector. With A/C switch in the on position, voltmeter should read approximately 12 volts. Turn A/C switch to off position. Measure voltage between terminals No. 2 and 8. Voltmeter should read zero volts.
Using an ohmmeter, check continuity between terminals No. 3, 4, 8 and ground. Continuity should exist.
Using a voltmeter, measure voltage between terminals No. 3 and 9. With engine coolant temperature at 172°F (78°C), voltmeter should read 12 volts. With engine temperature at 185°F (85°C), check voltage between terminals No. 8 and 9. Voltmeter should read zero volts.
Turn A/C switch to economy position (Amber light). Measure voltage between terminals No. 3 and 10. Voltmeter should read 12 volts. Turn A/C switch to off position. Measure voltage between terminals No. 8 and 10. Voltmeter should read zero volts.
If ohmmeter and voltmeter readings are within specification, replace A/C control unit.

Fig 1: Locating A/C Control Unit

Courtesy of CHRYSLER CORP.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

A/C Control Unit