Pinpoint Test C : One Or Both Low Beams Are On Continuously

WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.

C1 CHECK LOW BEAMS OPERATION
- Ignition ON.
- Place the headlamp switch in the OFF position.
- Observe the operation of the LH and RH low beam.
Are both low beams illuminated?

Yes GO to C2

No GO to C7

C2 CHECK THE HEADLAMP SWITCH
- Ignition OFF.
- Disconnect: Headlamp Switch C205 .
- Carry out the headlamp switch component test. Refer to Wiring Diagrams Component Testing for schematic and connector information.
Does the headlamp switch pass the component test?

Yes GO to C3

No INSTALL a new headlamp switch. REFER to: Headlamp Switch .

C3 CHECK THE HEADLAMP SWITCH GROUND CIRCUIT FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C205-4	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to C4

No	REPAIR the circuit.

C4 CHECK THE HEADLAMP SWITCH CIRCUITS FOR A SHORT TO VOLTAGE

Ignition ON.

Disconnect: BCM C2280B .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C205-10	Courtesy of FORD MOTOR COMPANY	C205-4
C205-11	Courtesy of FORD MOTOR COMPANY	C205-4
C205-12	Courtesy of FORD MOTOR COMPANY	C205-4
C205-13	Courtesy of FORD MOTOR COMPANY	C205-4

Is any voltage present?

Yes	REPAIR the circuit in question.

GO to C5

C5 CHECK THE HEADLAMP SWITCH CIRCUITS FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C205-10	Courtesy of FORD MOTOR COMPANY	Ground
C205-11	Courtesy of FORD MOTOR COMPANY	Ground
C205-12	Courtesy of FORD MOTOR COMPANY	Ground
C205-13	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes

GO to C6

No	REPAIR the circuit in question.

C6 CHECK THE HEADLAMP SWITCH CIRCUITS FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C205-10	Courtesy of FORD MOTOR COMPANY	C2280B-16
C205-11	Courtesy of FORD MOTOR COMPANY	C2280B-2
C205-12	Courtesy of FORD MOTOR COMPANY	C2280B-15
C205-13	Courtesy of FORD MOTOR COMPANY	C2280B-21

Are the resistances less than 3 ohms?

Yes

GO to C13

No	REPAIR the circuit in question.

C7 CHECK FOR HCM (HEADLAMP CONTROL MODULE) DIAGNOSTIC TROUBLE CODE (DTCS)
- Ignition ON.
- Using a diagnostic scan tool, perform the HCM self-test.
Is DTC B1087:00 or B1088:00 present?

Yes GO to C10

No GO to C8

C8 CHECK THE HEADLAMP INTERNAL HARNESS
- Place the headlamp switch in the OFF position.
- CHECK the internal headlamp harness for open or shorted circuits and damaged or pushed-out pins.
Is the headlamp internal harness OK?

Yes GO to C9

No REPAIR the harness. If the harness cannot be repaired, INSTALL a new headlamp assembly. REFER to: Headlamp Assembly .

C9 CHECK THE LED (LIGHT EMITTING DIODE) CONTROL MODULE

REMOVE the suspect LED control module (mounted on headlamp assembly).

Substitute the known good LED control module from the opposite headlamp.

CLEAR the Diagnostic Trouble Codes (DTCs), REPEAT the self-test (required to enable the lamp output driver) and cycle the ignition OFF and ON. TEST the system for normal operation.

Does the suspect headlamp operate?

Yes	REMOVE the known good LED control module. INSTALL a new LED control module. REFER to: Light Emitting Diode (LED) Control Module .

No	REMOVE the known good LED control module. INSTALL a new headlamp assembly. REFER to: Headlamp Assembly .

C10 CHECK THE HCM (HEADLAMP CONTROL MODULE) LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO VOLTAGE

Place the headlamp switch in the OFF position.

Ignition OFF.

Disconnect: HCM C2129 .

Disconnect: LH Headlamp C1758 or RH Headlamp C1759 .

Ignition ON.

Measure:

LH Headlamp

Positive Lead	Measurement / Action	Negative Lead
C2129-10	Courtesy of FORD MOTOR COMPANY	Ground

RH Headlamp

Positive Lead	Measurement / Action	Negative Lead
C2129-21	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to C11

C11 CHECK THE HCM (HEADLAMP CONTROL MODULE) LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND

Ignition OFF.

Measure:

LH Headlamp

Positive Lead	Measurement / Action	Negative Lead
C2129-10	Courtesy of FORD MOTOR COMPANY	Ground

RH Headlamp

Positive Lead	Measurement / Action	Negative Lead
C2129-21	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to C12

No	REPAIR the circuit.

C12 CHECK THE HCM (HEADLAMP CONTROL MODULE) LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR AN OPEN

Measure:

LH Headlamp

Positive Lead	Measurement / Action	Negative Lead
C2129-10	Courtesy of FORD MOTOR COMPANY	C1758-11

RH Headlamp

Positive Lead	Measurement / Action	Negative Lead
C2129-21	Courtesy of FORD MOTOR COMPANY	C1759-11

Is the resistance less than 3 ohms?

Yes

GO to C14

No	REPAIR the circuit.

C13 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION

Disconnect and inspect all BCM and all related in-line connectors.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Reconnect the BCM and all related in-line 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 service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, BCM guided routine is not applicable for this vehicle and market. Replace the component that was faulted through service information diagnosis.

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.

C14 CHECK FOR CORRECT HCM (HEADLAMP CONTROL MODULE) OPERATION

Disconnect and inspect the HCM connector.

Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

Reconnect the HCM connector. Make sure it seats and latches correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes	CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new HCM. REFER to: Headlamp Control Module (HCM) .

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.