| | Results of the tests |
| 1 | CHECKING ELECTRICAL EQUIPMENT | All OK | Problems met | Operation |
|---|
| 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. 4110A11Search for the fault starting
from another symptom' |