1994 Other Mitsubishi Models 3000GT with no power / possible

Hello, I have a 1994 3000GT SL. It is naturally aspirated V6 DOHC, two wheel drive with an automatic Transmission. I've had this car for only a week.

The factory alarm system was replaced by a system called the black widow. The lady who sold me the car told me she had had a dead battery and did not know the code to reporgram the remote, so she had just been using the key to open the doors and start the car.

The car ran fine for the first two days after I bought it, but I decided to try a new battery in the remote to see if the door locks would work. After putting the new battery in the remote, the remote lit briefly then went dark, but the door locks still wouldn't work. I later drove the car to the store, and when I turned it off in the parking lot and returned a few minites later, the car was dead and would not start. It will not jump start either. The car has no power whatsoever, not even the dome light will come on. Testing has confirmed that the battery is fully charged, and all three of the fusible links leading to the fuse box are good. All of the fuses are good, and I've checked all of the ground points and battery cables for resistance. I've tested the MFI relay and inspected the computer for leaks on the circuit boards. The cars fuel pump will still run if 12 volts are applied to the test terminal.

When a test light is connected to the negative battery post and any other ground point, such as a bolt for the strut support or on the bracket that holds the radiator, the test light will light steady for about 3 to 4 seconds, then begin to flash. When the test light flashes, the red LED for the security system flashes as well. No other circuits work, just the red LED on the alarm system.

There is an alarm system immobilizer relay located on the left side of the consol, but according to the Mitsubishi manuals this relay is for the factory system, and by-passing it doesn't work. I can't find any information on how the immobilzer system works. Does it cut all power from the car? Or just the starter circuit? At this point, I'm not sure if my problem is related to the alarm or not. Have you ever heard of any other cars having similar problems?

Any troubleshooting advice or information you could provide would be appreciated.

Thank you.