22 · Diagnostics

Horns not working

Make: Fiat
Model: Stilo Factory Service Manual
Year: 2001–2007
Section: Radio and accessories etc. › Horns not working

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Fault diagnosisHorns not working

HORNS NOT WORKING

1	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
		Results of the tests
	Change horn circuit fuse on engine bay control unit See E3010 HORNS	Continue to Step 2	Fuse broken	Check for short circuits in the wiring before changing the fuse See E3010 HORNS
2	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Disconnect the horn relay and check that there is supply voltage for the energizing circuit and the power circuit in the engine compartment control unit. See E3010 HORNS	Continue to Step 3	No voltage	Change engine bay control unit Op. 4110A11
3	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check horn control relay is working properly	Continue to Step 4	Relay faulty	Change relay
4	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Operate the button on the steering wheel and, using a multimeter in the engine compartment control unit, check the efficiency of the earth control for the horn relay energizing circuit See E3010 HORNS	Continue to Step 6	No earth control	Continue to Step 5
5	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Disconnect the relevant connector from the engine bay control unit. Operate the steering wheel button and use a multimeter to check the earth control See E3010 HORNS	Continue to Step 17	No earth control	Continue to Step 9
6	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check continuity of the horn earth connection See E3010 HORNS	Continue to Step 7	Earth interrupted	Renew the wiring See E3010 HORNS
7	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check the horn positive supply is present See E3010 HORNS	Continue to Step 16	Positive supply missing	Continue to Step 8
8	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check continuity of the wiring from the horn to the engine bay control unit See E3010 HORNS	Continue to Step 17	Wiring broken	Renew the wiring See E3010 HORNS
9	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check the continuity of the wiring from the connector involved at the engine compartment control unit to the clock spring See E3010 HORNS	Continue to Step 12	Wiring broken	Continue to Step 10
10	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check the continuity of the wiring from the clock spring to the intermediate connection See E3010 HORNS	Continue to Step 11	Wiring broken	Renew the wiring See E3010 HORNS
11	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check the continuity of the wiring from the intermediate connection to the connection at the engine compartment control unit See E3010 HORNS	Continue to Step 12	Wiring broken	Renew the wiring See E3010 HORNS
12	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check the continuity of the clock spring earth lead See E3010 HORNS	Continue to Step 13	Wiring broken	Renew the wiring See E3010 HORNS
	Change the continuity of the horn leads in the clock spring See E3010 HORNS	Continue to Step 12	Wiring broken	Replace the clock spring Op. 5580C12
13	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Change the continuity of the horn leads in the clock spring See E3010 HORNS	Continue to Step 15	Wiring broken	Replace the clock spring Op. 5580C12
	Change the continuity of the horn leads in the clock spring See E3010 HORNS	Continue to Step 14	Wiring broken	Replace the clock spring Op. 5580C12
14	CHECKING ELECTRICAL EQUIPMENT	All OK	Problems met	Operation
	Check the continuity of steering wheel node NVO and connection leads to buttons	Continue to Step 15	Circuit broken	Replace NVO
15	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the horn is working properly	End of diagnosis	Horn not working	Change steering wheel Op. 5505A13
16	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the horn is working properly	End of diagnosis	Horn not working	Replace the horn Op. 5550B30
17	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the horn is working properly		Horn not working	Change engine bay control unit Op. 4110A11 Search for the fault starting from another symptom'

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Parts & tools for this job For 2001 Fiat Stilo

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