horn problems, Diagnosis needed

[cooa99]

Hi all,

My Horn stopped working recently on my E53 3.0d sports

Here are the fault testing that I have done so far.

1) The 2 horns work when powered from the battery
2) While my daughter pressed the horn I connected a circuit tester in the bonnet to the wires going to the horn but tester does not light up
3) I checked the fuse box in the glove box to confirm presence of 12v supply. Also tested the 2 top ends of the 15A fuse and can confirm 12v presence
4) Took the glove box out to get to the back of the fuse box where the horn & fuel pump relays are situated. swapped the fuel pump relay with the horn relay and the horn still does not sound at all.

So this leaves me with the sports steering wheel as the only place left to check. Are there any precautions that i need to take since this is where the airbag is situated? Not sure what exactly I will be testing here....?

Also does the horn work only with the engine tuning or also with the keys in the accessory & On position? ...never paid attention to this

help really appreciated

Thanks