Diagnostic Test

WARNING: This page is about a different car, the 2008 Dodge Magnum, 2008 Dodge Charger, and 2008 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

CHECK (C105) HVAC MUX CONTROL CIRCUIT VOLTAGE AT A/C HEATER CONTROL C1 HARNESS CONNECTOR

Fig 1: Measuring Voltage Of HVAC MUX Control Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off.

Disconnect the A/C Heater Control C1 harness connector.

Turn the ignition on.

Measure the voltage of the (C105) HVAC MUX Control circuit.

Is the voltage below 4.8 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 .
CHECK (C105) HVAC MUX CONTROL CIRCUIT FOR A SHORT TO GROUND

Fig 2: Checking A/C Switch Sense Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off.

Disconnect the Instrument Cluster C2 harness connector.

Measure the resistance of the (C105) HVAC MUX Control circuit between ground and the A/C Heater Control C1 harness connector.

Is the resistance below 10K ohms?

Yes
1. Repair the (C105) HVAC MUX Control circuit for a short to ground.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Go To step 3.
CHECK (C105) HVAC MUX CONTROL CIRCUIT FOR AN OPEN

Fig 3: Checking HVAC MUX Control Circuit For Open
Courtesy of CHRYSLER LLC

Measure the resistance of the (C105) HVAC MUX Control circuit between the A/C Heater Control C1 harness connector and the Instrument Cluster C2 harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Replace the Instrument Cluster (CCN) in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Repair the (C105) HVAC MUX Control circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1 .