B1001

B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW (CCN)

B1001-A/C Switch Request Input Circuit Low (CCN):

WHEN MONITORED
With the ignition on.

SET CONDITION
If the Instrument Cluster (CCN) detects voltage below 0.55 volts for 10 seconds on the (C105) HVAC MUX Control circuit.

POSSIBLE CAUSES
- (C105) HVAC MUX control circuit shorted to ground
- (C105) HVAC MUX control circuit shorted to (Z906) ground circuit
- (C105) HVAC MUX control circuit shorted to (C955) HVAC MUX return circuit
- Instrument cluster (CCN)
- A/C heater control

Diagnostic Test

1. VERIFY DTC B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW IS ACTIVE

Turn the ignition on.
With the scan tool, erase CCN DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read CCN DTCs.

Q: Does the scan tool display active: B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW?

YES: Go To 2
NO: Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test




2. CHECK FOR B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW WITH A/C HEATER CONTROL C1 HARNESS CONNECTOR DISCONNECTED

Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
With the scan tool, erase CCN DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read CCN DTCs.

Q: Does the scan tool display: B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW?

YES: Go To 3
NO: Replace the A/C Heater Control. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test




3. CHECK THE (C105) HVAC MUX CONTROL CIRCUIT FOR A SHORT TO GROUND

Turn the ignition off.
Disconnect the Instrument Cluster C4 harness connector.
Measure the resistance of the (C105) HVAC MUX Control circuit between ground and the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms?

YES: Repair the (C105) HVAC MUX Control circuit for a short to ground. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 4




4. CHECK THE (C105) HVAC MUX CONTROL CIRCUIT FOR A SHORT TO THE (Z906) GROUND CIRCUIT & THE (C955) HVAC MUX RETURN CIRCUIT

Measure the resistance between the (C105) HVAC MUX Control circuit and the (Z906) Ground circuit in the A/C Heater Control C1 harness connector.
Measure the resistance between the (C105) HVAC MUX Control circuit and the (C955) HVAC MUX Return circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms on either circuit?

YES: Repair all circuits with a resistance below 10k ohms for a short to the (C105) HVAC MUX Control circuit. Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the Instrument Cluster (CCN). Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test