On US Standard vehicles, it should be under OUR passanger side fender. (the right side) check over there. its kinda hidden, if its not there, yours might be on the other side which would be more accessable.
P.S. call up my business, i run a salvage yard, i have a horn for you. Dont pay dealer price [:D].
OK... i appologize, i shouldve asked you this question before i answered yours... is your alarm horn the "police style" whining horn... or is it the conistent beeping style? if its the beeping style, then that should be located on the passenger side, by the fender, on the engine subframe (check the frame near it too, it might be there) if its the whining style, then i honestly do not know where that one is. I hope that helped you any....
If your 98 is anything like my 97, hopefully I can point you in the right direction...
First thing to realize is you have 2 horns and 1 alarm so don't confuse them. In case your wondering, the high pitch horn is in the grill and the low pitched horn is behind/below the passenger side headlight.
For the alarm horn, lift the hood and look to the left side, behind and left of the air filter casing. It's about the size of a computer mouse and sort of looks like it's got a horn end on it. The good news is it's the easiest on to get to and replace. I'm about 99% sure it's on the passenger side, but just in case, look on the drivers side too...
thanxs for the input gents......i am assuming that the european set up is obviously different from the US version..........anybody from the UK have any answers for me????
found it...........its on the right hand wing/....fender for our US cousins...you need to remove the plastic inner wing/fender and its bolted to the back of of the chasis
you never knoe the information might be of use to some other member some day