Reset alarm

I would try a hard reboot which means to hold the negative battery cable to the positive terminal for one minute this will discharge the capacitors in the system and let it reboot. Here is a guide to help you:

https://www.2carpros.com/articles/how-to-reset-a-security-system

Please run down this guide and report back.

Cheers

Is it factory installed or is it after market?

I just got the vehicle, but it was a lease back, so I am sure that it would be factory installed.

Check with dealer to make sure they did come from dealer with alarm if they say it is not factory then under dash driver side there should be a black box hidden under therewith a bunch of wires coming out of it going to the ignition module. Unscrew the one bolt remove the adapter and put back together now the alarm is no longer. But if they say it is factory they will have to disable it you cannot not with out shutting down whole electrical system.

Thanks for your help!

If any water gets near fuses or body module on drivers side inside will cause this problem. Did to mine after a hard rain and after a few warm no rain days hooked battery back up and my Cecile would work okay again. Mine has a cracked windshield and water is getting in near this area so try blowing this area out with air hose to remove the water if you have any could be your problem. Time for a new windshield for me. After new windshield mine working the way it should. As for disable alarm dealership said with factory alarm they cannot turn off. It is located in body module at $1,000.00 plus labor. Glad mine was only a bit of water. Hope this helps someone.