K91 INSTRUMENT LIGHTS / LIGHTING DIMMER NOT WORKING - Alfa - 156 - eLearn

With the ignition turned on ON and the side lights on, the instruments are properly lit but the intensity is not adjustable.

1	CHECKING INSTRUMENT LIGHTING DIMMER BUTTON	All OK	Problems met	Operation
		Results of the tests
	Check instrument lighting dimmer button operation ( See E2530 INSTRUMENT LIGHTING ).	Continue to Step 2	Instrument lighting dimmer button faulty	Repair or replace the instrument lighting dimmer button Op. 5540C18
2	CHECKING INSTRUMENT LIGHTING DIMMER ELECTRICAL CIRCUIT	All OK	Problems met	Operation
	Check, in order: Connection between speedometer and instrument lighting dimmer control lighting dimmer control earth connection between speedometer and other instruments connection between stalk unit and instrument lighting dimmer control ( See E2530 INSTRUMENT LIGHTING ).	Continue to Step 3	Connection broken	Restore connection
3	SPEEDOMETER CHECK	All OK	Problems met	Operation
	Check operation of the speedometer, particularly the instrument lighting dimmer function: see DESCRIPTION AND OPERATION: 5560 INSTRUMENT PANEL	Continue to Step 4	Instrument not working	Replace the speedometer Op. 5560B02
4	CHECK CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'