Workshop Manuals Factory service & repair Alfa Romeo
01 General information02 Specifications03 Manufacturing data and tolerances04 Tightening torques05 Fluids and lubricants06 Maintenance07 Diagnostic checks08 Engine09 Clutch10 Gearbox and differential11 Transmission (4x4)12 Axles and driveshafts13 Brakes14 Steering15 Suspension and wheels16 Heating, air conditioning and auxiliary units17 Electrical equipment18 Body fittings19 Body panels and frame20 Wiring diagrams and electrical functions21 Wiring harnesses22 Connectors and pin-outs23 Fault diagnosis24 Special tools
Alfa Romeo Brera and Spider Factory Service Manual (2005-2010)23 · Fault diagnosis
23 · Diagnostics

Horns working endlessly

Make
Alfa Romeo
Model
Brera and Spider Factory Service Manual
Year
2005–2010
Section
Radio and accessories etc.. › Horns working endlessly
Fault diagnosisHorns working endlessly

HORNS WORKING ENDLESSLY

1RELAY CHECKALL OKPROBLEMS ENCOUNTEREDACTION

Remove the horn relay feed and check that the horns stop making a sound.

Swap the horn relay feed T3 (it is the middle one in the top row) with the one for the main beam headlamps T (it is the first on the left in the top row) and check that the horns worn properly.

Move on to Step 21. The horns continue to make a sound even without the relay

1. Restore the correct electrical connections

See E3010 HORNS

2. The horns continue to sound without being pressed even after the relays have been swapped.2. Restore the relays to their places and move on to Step 3
2RELAY CHECKALL OKPROBLEMS ENCOUNTEREDACTION

Check that the main beam headlamps are working properly.

If the result is positive, remove the horn relay feed and check that the contacts do not show signs of oxidation or deformation.

End of diagnosis1. The main beam headlamps remain on in all conditions1. Replace the main beam headlamp relay (which was originally the one for the horns)
2. There are irregularities at the engine compartment junction unit contacts.

2. Renew the contacts. If necessary, replace the engine compartment junction unit

Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

3HORN ELECTRICAL CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Connect a tester to the horn supply line and check the continuity and the insulation of the line.Move on to Step 4Electrical faults: engine compartment junction unit defective.

Replace the engine compartment junction unit

Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

4STEERING COLUMN SWITCH UNIT CHECKALL OKPROBLEMS ENCOUNTEREDACTION
Remove the steering wheel and check that there is nothing preventing the operation of the horn control switch.Move on to Step 5Switch stuck in closed position.

Replace the steering column switch unit.

Op. 5550A10 STALK UNIT ASSEMBLY - R+R

5ELECTRICAL CIRCUIT CHECKALL OKPROBLEMS ENCOUNTEREDACTION

The problem is due to the presence of a short circuit in the electrical system

See E3010 HORNS

Search for and eliminate this cause.

End of diagnosis

Parts & tools for this job For 2005 Alfa Romeo Brera

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