Re: Security light
This seems to be a PCI data bus problem. The SKIM is communicating with the PCM via the PCI bus, to tell that a valid key is used. With the PCI bus down, this signal is not received and the engine starts and runs for a few seconds and shutts off. Due to the PCI bus down, the instrument cluster will light all lights, but instruments will not work, EVIC will show only dashes, power lock on drivers side will not work and an other bunch of things.
If your key was the problem, the engine would start and shutt down, but all other indications and systems would be ok.
Do you have an XJ, or WJ? Don't know the XJ, but for the WJ there is a diagnostic juntion port below the steering wheel, where all PCI wires come together and a shorting cap makes the connection between all. When you take the disconnect cap off, you isolate most of the systems, exept PCM, TCM and SKIM will still be connected together. Now you can start and see if the engine runs ok. The instrument cluster will not be working at this time, because its PCI bus is disconnected.
Since you have a problem with the drivers door motor, it could be that it locks up the drivers door module, which is connected to the PCI bus. Now you can connect each component via the diagnostic junction port to point 1 (which is connected to PCM/TCM/SKIM) and see if the problem returns. You could also measure the PCI bus voltage at the connector where you plug the scanner, it should be 0-2 Volts and fluctuating, showing the data signal. If its 0V all the time, a wire or a component is shorted. If its 4-7 V, a component has an internal failure and increases the bus voltage.
Also have a look at the following thread, where i posted some wiring schematics, which shows all components connected to the diagnostic junction port and also the position of this port.