Location of horns on 1998 R129 500SL

Hope you can help.
The horn on our R129 is sounding weak. I have couple of questions;
a) Is it twin tone i.e. has two horns?
b) What is the best way to get at it/them? From the wheel arch or from behind the headlamp or someother way?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.