Pinpoint Test I : The Defrost System Does Not Shut Off Automatically

I1 CHECK FOR BCM (BODY CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)

Ignition ON.

Using a diagnostic scan tool, perform BCM self-test.

Are any BCM Diagnostic Trouble Codes (DTCs) present?

Yes	For DTC B112D:15, GO to I2 For DTC B1C84:11 or B1C84:14, GO to I5 For all other Diagnostic Trouble Codes (DTCs), REFER to DTC Chart: Body Control Module (BCM) .

GO to I3

I2 CHECK FOR A SHORT TO VOLTAGE IN THE DEFROST SWITCH LED (LIGHT EMITTING DIODE) CIRCUIT

Ignition OFF.

Disconnect: Rear Window Defrost/Heated Windshield Switch C2805.

Disconnect: BCM C2280C.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C2805-9	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

No	INSTALL a new rear window defrost/heated windshield switch.

I3 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
Courtesy of FORD MOTOR COMPANY Rear Window Defrost Relay, socket pin 5, circuit CRD06 (BN/YE)	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to I4

I4 CHECK FOR A SHORT TO GROUND IN THE REAR WINDOW DEFROST RELAY CONTROL CIRCUIT

NOTE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this article. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.

Connect a 12-volt incandescent test light between:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY Rear Window Defrost Relay, socket pin 1, circuit SBB23 (WH/RD)	Courtesy of FORD MOTOR COMPANY	Courtesy of FORD MOTOR COMPANY Rear Window Defrost Relay, socket pin 2, circuit CRD02 (BN/BU)

Does the test light illuminate?

Yes

GO to I5

No	INSTALL a new rear window defrost relay.

I5 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 (if not previously disconnected).

Disconnect: BCM C2280B.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Rear Window Defrost Relay, socket pin 2, circuit CRD02 (BN/BU)	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to I6

No	REPAIR the circuit.

I6 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION

Ignition OFF.

Inspect 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.