Re: 2001 Jeep Grand Cherokee 4.0
Welcome to the garage.
Not sure which part you are refering to when saying that the security system is all in the door, as far as i know there is nothing in the door, besides the ajar switches for the car alarm, but that is separate from the SKIM system.
Did you check the fuses #7 and #22 on the junction block under the drivers side dash?
Does the SKIM key light come on and go out when putting ignition in run?