Every year as summer (!) dawns we get a few occasions where the alarm is triggered, usually in the middle of the night, and always without an obvious cause.

Having noted the LED pattern, it is the internal motion sensor being activated, I presume from an insect or somesuch having a party in the car.

Is this a straightforward DIY disable, or is this a Fiat garage job?

My handbook says:

"To deactivate the volumetric surveillance: the volumetric protection function can be deactivated before activating the electronic alarm in this way: turn the ignition key from STOP and bring it in rapid succession onto MAR then back to STOP, after which, remove the key.

The LED on the instrument panel (the one by the coin slots) will light up for about 2 seconds to confirm that the sensors have been cut off.

To reactivate volumetric protection (before enabling the electronic alarm) turn the key to MAR for more than 30 seconds.

If however, the volumetric protection has been deactivated and you wish to operate one of the electronic controls managed by the ignition key in MAR (e.g. electric windows) turn the key to MAR, use the required electric control then bring the key back to STOP within 30 seconds. In this way the volumetric protection will not be reactivated"

Best of luck.....

That works; I had to do that as, first, water dripping in from the rear sunroof was setting it off and secondly, the sat nav mount losing its suction on the windscreen and falling off.
The first was solved by the liberal application of gaffer tape. Don't mock, it was a proper job, with no creases and I bought black tape to match the black car.

FYI, two things help cure the leaking issue and still retain use of the roofs.

1. cleaning the surface of the rubber where it comes in contact with the glass roof and the glass itself to ensure a good seal

2. Captain Tolly's Creaping Crack cure run all the way around the beading where the rubber seal actually contacts the metal roof tends to create a long lasting solution.

http://www.captaintolley.com/

Thanks for that, in the dim and distant past I do remember reading that.

In "rapid succession" I presume means just go from STOP to MAR and back quickly, not some nonsense about toggling it frm STOP to MAR a few times rapidly?

Will give that a go tonight.

Sorted, thanks.