Need help removing this security system someone had installed on here before

 

Where is the actual alarm module? maybe once you find that someone will be able to help a little better, Personally I would just find where the wires were tapped into factory wires and start removing them.

 

x2, find the module. Also, some of them tie into the fuel pump or other methods to cut it out. Make sure you find that module and get a model # and such off of it. If the unit isn't being used, it's probably disabled anyways. Most common place is under the dash however they may have found a more creative place to hide this one (under console, etc) as it's an alarm.