1991 560SEL horn

[alabbasi]

All

I'm trying to debug the horn which is not working. Here is what I have done so far.

1) Removed steering wheel - Contacts appear to be in good shape. Sprayed WD 40 and tested with mutli meter. I'm not getting any voltage.
2) Removed fan fare switch and tested with volt meter, no voltage
3) Tested horns by running a wire directly to fuse 7. Horns work.

I checked the wiring diagram (see attached) and the only thing that i can think of is that the problem is at x63.

What is x63 and where is it located?

Many thanks