When I press horn for about 30 sec fuse blows out
 

When I press horn for about 30 sec fuse blows out, what can it be, is it time for a new horn I don't think is wiring because then it would work period, Any advise

Why would you need to honk for 30 seconds? Does the fuse blow if you honk for one or two seconds?

OK not 30 seconds, Yes the fuse blows if I do a few seconds, lets say 5 seconds

Too much current draw, either due to a wiring fault (short to ground);

or a failed horn (too much current draw);

or wiring modifications (such as adding additional load to that circuit);

or the wrong size fuse.

Have you or anybody added any electrical devices such as aftermarket sounds system components, larger horn, etc?

Have not added anything new to car, is it possible to horn to work but keep blowing fuse, can I increase the fuse from 15 to 20? without damage

The horn can draw too much power and still sound, yes.

No, it is not safe to just put a larger fuse in. The wiring is rated for the correct fuse.

I don't have an X5 fuse box to look at, but do you know what the correct fuse rating is? It should say on the fuse box.

Do you know if one of the two horns is drawing too much power? If you don't have an ammeter, unplug them one at a time.

Horn amp says 15, I did not know my car had two horn,

It looks like this, one higher frequency and one lower frequency.

RealOEM.com * BMW E53 X5 4.4i Horn

New York. Figures. Who else would need their horn to blast for 30 seconds? :D

Another thought is that it might even be less of a hassle to completely move out of the city/change jobs and relocate to an area where one doesn't need a horn than to troubleshoot an X5 electrical gremlin.:D