Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) CHECK (C221) A/C SWITCH SENSE CIRCUIT VOLTAGE AT A/C HEATER CONTROL C1 HARNESS CONNECTOR

Fig 1: Checking A/C Switch Sense Circuit Voltage At A/C Heater Control C1 Harness Connector
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the A/C Heater Control C1 harness connector.

Turn the ignition on.

Measure the voltage of the (C221) A/C Switch Sense circuit.

Is the voltage above 5.2 volts?

Yes
1. Go To step 2).
No
1. Replace the A/C Heater Control in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1 .
2) CHECK (C221) A/C SWITCH SENSE CIRCUIT FOR A SHORT TO VOLTAGE

Fig 2: Checking A/C Switch Sense Circuit Voltage At A/C Heater Control C1 Harness Connector
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Instrument Cluster C3 harness connector.

Turn the ignition on.

Measure the voltage of the (C221) A/C Switch Sense circuit.

Is the voltage above 0.2 volts?

Yes
1. Repair the (C221) A/C Switch Sense circuit for a short to voltage.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Replace the Instrument Cluster (CCN) in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1 .