22 · Diagnostics

Main beam headlamps not working

Make: Lancia
Model: Thesis Factory Service Manual
Year: 2002–2009
Section: Lights › Main beam headlamps not working

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Fault diagnosisMain beam headlamps not working

MAIN BEAM HEADLAMPS NOT WORKING

The main beam headlamps are not working in any conditions (either in the stable lever position or flasher position);

The main beam headlamps are controlled by the Body Computer Node via a relay located in the Engine Compartment Junction Unit; the lights can be switched on/off using the following controls:

The main beam headlamps are controlled by the Body Computer Node via a relay located in the Engine Compartment Junction Unit; the lights can be switched on/off using the following controls:
1 Command from steering column switch unit in fixed position with go ahead via the Exterior Lights Control
2 Command from the steering column switch unit in "Flasher function" unstable position
The main beam headlamp consists of a traditional bulb (known as the "auxiliary main beam") and an electronic module connected in parallel to the bulb which supplies a coil which controls a partition which completely releases the xenon dipped headlamp.

The main beam headlamp consists of a traditional bulb (known as the "auxiliary main beam") and an electronic module connected in parallel to the bulb which supplies a coil which controls a partition which completely releases the xenon dipped headlamp.

STEP	OPERATIONS TO BE CARRIED OUT	TEST RESULTS
1	CHECK USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Connect the Examiner diagnostic equipment to the diagnostic socket and check the following at the Body Computer Node: that there are no faults in the Main Beam Headlamps Relay the operation of the relay through active diagnosis the plausibility of the main beam headlamps on parameter	Move on to Step	1. Presence of faults in main beam headlamps relay	1. Continue following the instructions for the diagnostic equipment
			2. The main beam headlamps relay is not activated	Move on to Step
			3. Parameter not plausible	Move on to Step
2	RELAY SUPPLY FUSE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the condition of the fuse for the main beam headlamps control circuit in the Engine Compartment Junction Unit (Wiring Diagram ) E2012 MAIN BEAMS	Move on to Step	Fuse blown	Replace the fuse (Wiring Diagram ) E2012 MAIN BEAMS
3	MAIN BEAM HEADLAMPS RELAY CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the condition of the main beam headlamps relay	Move on to Step	Relay defective	Replace the relay
4	CHECK ON ELECTRICAL SYSTEM INSIDE ENGINE COMPARTMENT JUNCTION UNIT (control circuit)	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the continuity of the connection for the control circuit for the main beam headlamps inside the engine compartment junction unit (Wiring Diagram ) E2012 MAIN BEAMS	Move on to Step	Connections inside engine compartment junction unit interrupted	Replace the engine compartment junction unit See in Op. 5505A13 Additional junction unit in engine compartment - R.R.
5	ELECTRICAL SYSTEM CHECK.	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the continuity of the wiring connecting the engine compartment junction unit and the Body Computer Node (Wiring Diagram ) E2012 MAIN BEAMS	Move on to Step	Connection broken	Restore the electrical connection (Wiring Diagram ) E2012 MAIN BEAMS
6	CHECK ON ELECTRICAL SYSTEM INSIDE THE ENGINE COMPARTMENT JUNCTION UNIT (power circuit)	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the continuity of the connection for the power circuit for the main beam headlamps inside the engine compartment junction unit (Wiring Diagram ) E2012 MAIN BEAMS	Move on to Step	Connection broken	Restore the electrical connection (Wiring Diagram ) E2012 MAIN BEAMS
7	STEERING COLUMN SWITCH UNIT OPERATION CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the operation of the steering column switch unit in the main beam headlamps position (Wiring Diagram ) E2012 MAIN BEAMS	Move on to Step	open circuit for steering column switch unit internal line	Replace the steering column switch unit See in Op. 5550A12 complete stalk unit - r+r for versions with air bag
8	ELECTRICAL SYSTEM CHECK.	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the continuity of the connections between the steering column switch unit and the Exterior Lights Control (Wiring Diagram ) E2012 MAIN BEAMS	Move on to Step	Interruption or no insulation for the connecting cables	Restore the electrical connection (Wiring Diagram ) E2012 MAIN BEAMS
9	EXTERIOR LIGHTS CONTROL OPERATION CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the operation of the connection to earth for the exterior lights control with the dipped headlamps position switched on (See test 5540AA) Continue following the instructions in the test 5540AA Exterior lights control operational check (C.L.E.)	Move on to Step	Exterior lights internal control interrupted	Replace the exterior lights control See in Op. 5540A20 Exterior lights SWITCH PANEL and instrument panel light dimmer - R.R.
10	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the fault is no longer present		Fault persists	Replace body computer See in Op. 5505A32 BODY COMPUTER - R.R.

‹ Prev Dipped headlamps not working Next › Right/left dipped headlamp (one) not working

Parts & tools for this job For 2002 Lancia Thesis

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