At some time in its life my TJ had an aftermarket alarm and remote start system installed, all of which became redundant before I took ownership. Today i wired in the siren from this system into the interior light circuit so it goes off if someone opens a door and triggers any of the interior lights, i installed a bypass system that cuts power to the siren allowing me to have the doors open without the siren operating, the cost just £2.45 for the switch from maplins. Whilst under the dash i removed some of the aftermarket system wiring and discovered a black box, curious I opened it and found the spare ignition key, it was under a wired loop, obviously the remote start system needed the chip code from a key to allow the vehicle to run. I thought I had just one key and had been considering getting another cut and programmed at considerable expense. Well chuffed, It was'nt long ago I found a muddy tender under the carpet!.