Hello and welcome to just answer. Do you know if your Jeep has the factory security alarm or an after market one? If you are not sure, send me the VIN# XXXXX I can look it up for you.
Have you tried using the key and manually unlocking each door including the lift gate?
Where is the light located that is blinking? And does it say "security" or ??
Ok, then the Security module (known as the SAM module) has probably failed and will need to be replaced. There is no way to "disable" the factory security system Because the SAM module is linked to the Jeeps PCM (engine computer). The PCM will always look to see if the SAM module says that it is ok to start and run. The only way to remove the security system is to first remove the SAM module and then purchase another PCM and install it. Once a PCM sees a SAM module then it "learns" that the vehicle has a SAM module and will always look for that "ok to run" message. If you remove the SAM module first and install a fresh PCM then the PCM will never see a SAM module and will never look for it. This really the only way to do this. If you want to keep the security system, then purchase a new SAM module.