22 · Diagnostics

(side) brake lights not working

Make: Lancia
Model: Thesis Factory Service Manual
Year: 2002–2009
Section: Lights › (side) brake lights not working

‹ Prev Brake lights and third brake light not working Next › Centre brake light (third brake light) not working

Fault diagnosis(side) brake lights not working

(SIDE) BRAKE LIGHTS NOT WORKING

The rear brake lights are not working; the third brake light is working normally;

The left and right brake lights are operated directly by the Body Computer Node using information coming from the brake lights switch.

The Body Computer Node directly controls the condition of the Brake Lights fuse and, using information coming from the rear light clusters via a dedicated serial line, the condition of the left and right Brake Lights. Faults in the rear light clusters and the fuse are memorized by the Body Computer Node and are displayed in the Instrument Panel Node via appropriate messages in the B-CAN.

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 at the Brake Lights the operation of the Brake Lights through active diagnosis the plausibility of the Brake Lights On/Off parameter	Move on to Step	1. Presence of error at Brake Lights bulb/fuse	1. Continue following the instructions for the diagnostic equipment
			2. The lights do not come on	Move on to Step
			3. The Brake Lights on/off parameter does not alter	Move on to Step
2	DASHBOARD JUNCTION UNIT CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Remove the dashboard junction unit, separate it from the Body Computer Node and check the internal continuity from the Brake Lights switch positive intake to the Body Computer Node	Move on to Step	Dashboard junction unit internal interruption	Replace the dashboard junction unit See in Op. 5505A10 Junction UNIT - R.R.
3	ELECTRICAL SYSTEM CHECK.	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the continuity/insulation between the Body Computer Node and the rear light clusters (Wiring Diagram ) E2021 BRAKE LIGHTS	Move on to Step	Wiring faulty	Restore the electrical connection (Wiring Diagram ) E2021 BRAKE LIGHTS
4	REAR LIGHT CLUSTERS CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the condition of the rear light clusters	Move on to Step	Rear light clusters faulty	1. Replace the left rear light See in Op. 5540A60 Left outside rear light cluster - R.R. 2. Replace the right rear light See in Op. 5540A62 Right outside rear light cluster - R.R.
5	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 Brake lights and third brake light not working Next › Centre brake light (third brake light) not working

Parts & tools for this job For 2002 Lancia Thesis

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