A/C Control Blend Door Input Open Or Shorted To Ground (Manual A/C)

WARNING: This page is about a different car, the 2002 Dodge Intrepid, 2002 Chrysler Intrepid, 2002 Chrysler Concorde, and 2002 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: After making any repairs, perform BODY VERIFICATION TEST under VERIFICATION TESTS.

Monitored & Set Condition

When Monitored: With ignition on.
Set Condition: The BCM detects an abnormal low voltage (below one volt) on its blend request input.

Possible Causes:

Fused Ignition Switch Output Circuit Open
Temperature Select CKT Shorted To Ground
Temperature Select CKT Shorted To Sensor Ground
Temperature Select CKT Open
Control Head - Temp Select Open/Short
Body Control Module - Temp Select Open/Short

Testing

With the scan tool, erase BODY CONTROL DTC's. Disconnect the manual temp control head C1 harness connector. See Figure . Turn ignition on. Using a 12-volt test light connected to ground, probe the fused ignition switch output circuit. If the test light illuminates, go to next step. If the test light does not illuminate, repair the fused ignition switch output circuit for an open.
Turn ignition off. Disconnect BCM C2 harness connector. See Figure . Measure the resistance between ground and the temperature select circuit. If the resistance is 100 ohms or less, repair the temperature select circuit for a short to ground. If the resistance is 100 ohms or more, go to next step.
Measure the resistance between the sensor ground circuit and the temperature select circuit. If the resistance is 100 ohms or less, repair the temperature select circuit for a short to ground. If the resistance is 100 ohms or more, go to next step.
Measure the resistance between of the temperature select circuit between the BCM C2 connector and the manual temp control head C1 connector. See Figure and Figure . If the resistance is 5 ohms or less, go to next step. If the resistance is 5 ohms or more, repair the temperature select circuit for an open.
Reconnect the manual temp control head C1 harness connector. With the BCM C2 harness connector still disconnected, turn ignition on. Measure the voltage of the temperature select circuit in the BCM C2 harness connector. Move the temperature control from cold to hot and observe the voltmeter. If the voltage changes smoothly from 1 volt (cold) to 10 volts (full hot), replace the BCM. See BODY CONTROL MODULE under REMOVAL & INSTALLATION. If the voltage does not change smoothly, replace the control head. See MANUAL A/C-HEATER SYSTEMS - CONCORDE & INTREPID article in HVAC.