Aerial fuse keeps blowing - any ideas why?

[AlpineCab]

Subject says it all really, all of a sudden fuse keeps blowing all the time leaving aerial stuck up...

7.5 amp blow, 15amp does not blow, <VIRTUOUS>but would rather sort the problem instead of frigging it with the 15amp.</VIRTUOUS>.

Had a search on the past posts, but can't find anything.

Why could this be happening?

[fowler]

two posiblities really but need to ask a question does the aeriel go up and down ?
if it does work then its probably a stiff aeriel motor and draws too much current or
IF it doesn't work then the there is a short in the motor and needs two replaced
it could also be that when the motor is supposed to stop it doesn't and again pulls too muich current and blows

[Adammcf]

The wire behind the dash where it connects to the radio signal may be bare and touching another wire or some metal.

[AlpineCab]

Fowler - Yes aerial does go up and down, I'll try and give it a clean up.

Adammcf - Could be, radio has been in, and out, and in, and out, the metal cage is a bit shot to pieces so could have snagged.

Cheers for the pointers!