Pinpoint Test B : The Defrost System Does Not Shut Off Automatically - EMTC (Electronic Manual Temperature Control)
- B1 CHECK FOR BCM (BODY CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Using a scan tool, perform BCM self-test.
Are any BCM Diagnostic Trouble Codes (DTCs) present?
Yes For DTC B112D:15, GO to B2. For DTC B1C84:11 or B1C84:14, GO to B4. For all other Diagnostic Trouble Codes (DTCs), REFER to: Body Control Module (BCM) . No GO to B3 - B2 CHECK FOR A SHORT TO VOLTAGE IN THE DEFROST SWITCH LED (LIGHT EMITTING DIODE) CIRCUIT
- Ignition OFF.
- Disconnect: HVAC C2357B .
- Disconnect: Ignition Relay.
- Disconnect: BCM C2280C .
- Connect a fused jumper wire:
Positive Lead Measurement / Action Negative Lead
Ignition Relay, socket pin 3
Ignition Relay, socket pin 5
- Measure:
Positive Lead Measurement / Action Negative Lead C2357B-15 Ground
Is any voltage present?
Yes REMOVE the fused jumper wire. REPAIR the circuit. No REMOVE the fused jumper wire. A guided routine is not applicable for this vehicle and market. Replace the component that was faulted through service information diagnosis. RETEST the system. If the concern is still present, GO to B5 - B3 CHECK FOR A SHORT TO VOLTAGE IN THE DEFROST GRID CIRCUIT
- Ignition OFF.
- Disconnect: Rear Window Defrost Relay.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead
Rear Window Defrost Relay, socket pin 5Ground
Is any voltage present?
Yes REPAIR the circuit. No INSTALL a new rear window defrost relay. - B4 CHECK FOR A SHORT TO GROUND IN THE REAR WINDOW DEFROST RELAY CONTROL CIRCUIT WITH THE BCM (BODY CONTROL MODULE) DISCONNECTED
- Ignition OFF.
- Disconnect: Rear Window Defrost Relay.
- Disconnect: BCM C2280C .
- Measure:
Positive Lead Measurement / Action Negative Lead
Rear Window Defrost Relay, socket pin 2Ground
Is the resistance greater than 10, 000 ohms?
Yes GO to B5 No REPAIR the circuit. - B5 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION
- Ignition OFF.
- Connect: Ignition Relay (if previously disconnected).
- Disconnect and inspect all the BCM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins as necessary
- pushed-out pins - install new pins as necessary
- Reconnect the BCM connectors and all previously disconnected rear window defrost system connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, Refer to BCM GUIDED ROUTINE TESTING No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.