Join Date: Jun 2007
My Motorhome: Hymer Exsis-i 504
Thanked 335 Times in 321 Posts
Do you have a fob GG?
I had the same problem with my alarm (can't remember the name but not the same as yours).
My fob has 4 symbols on it - a lock, unlock, boot open (??) and a wireless symbol - it's this last that sets the external perimeter alarm.
Took me ages to work that out - it didn't do anything to start with but it transpired that was because the battery was done!