Test results

Remove the relay for the horn and check that it stops sounding.

Check the insulation of the wiring between the button on the steering wheel and the horn

 See E3010 HORNS

Move on to Step 2

1. The horn continues to sound even without the relay

2. Wiring not correctly insulated

3. The horn stops working

1. Replace the engine compartment junction unit

 Op. 5505A28 CONTAINER FOR ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

2. Restore the correct insulation

3. Replace the relay

Check the insulation of the connection between the clock spring on the steering column switch unit and earth

 See E3010 HORNS

Move on to Step 3

1. Wiring insulation not correct between clock spring and earth.

2. Clock spring short circuited to earth

1. Restore the correct insulation

2. Replace the steering wheel interface

 Op. 5550A10 STALK UNIT ASSEMBLY - R+R

Check the button on the steering wheel is working properly

End of diagnosis

Button on steering wheel mechanically stuck

Replace the horn control

 Op. 5550B30 L/H OR R/H HORN (ONE) - R+R