Centre brake light (third brake light) not working

Fault diagnosisCentre brake light (third brake light) not working

CENTRE BRAKE LIGHT (THIRD BRAKE LIGHT) NOT WORKING

The third brake light is not working when the brake pedal is operated, whilst the rear brake lights are working normally;

The third brake light is controlled directly by the switch on the pedal assembly.

STEP	OPERATIONS TO BE CARRIED OUT	TEST RESULTS
1	ELECTRICAL SYSTEM CHECK.	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the following at the dashboard junction unit: a positive output to the third brake light bulb (Wiring Diagram ) E2021 BRAKE LIGHTS	Move on to Step	No positive output to the third brake light bulb	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 (Wiring Diagram ) E2021 BRAKE LIGHTS	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: left rear earth and third brake light bulb dashboard junction unit and third brake light bulb (Wiring Diagram ) E2021 BRAKE LIGHTS	Move on to Step	Wiring faulty.	Repair the electrical connections (Wiring Diagram ) E2021 BRAKE LIGHTS
4	THIRD BRAKE LIGHT BULB CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	check the condition of the third brake light bulb	Move on to Step	Bulb burnt out	Replace the third brake light bulb See in Op. 5550D16 third brake light - r r
5	CHECK ON CORRECT OPERATION.	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the fault is no longer present

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