Cadillac Allante Forum Discussion, 91 security system will not allow start. in Past Cadillac Vehicle Discussion; How can I by pass? Any tricks? When starting there is no sound at all. The read out says security ...
I stay at Holiday Inexpress and steal all Allante info I can copy. Hope this helps, from Scott Flack from Indiana:
Get an ohm meter and check the resistance across the resistor in your ignition key. Go to Radio Shack and buy 1/2 watt resistors that add up to the resistance you measured (within a few percentage points).
Remove the kick panel above your feet on the driver's side. Look for two light gage white wires beneath the steering column. These wires go from the ignition switch to the VATS computer (which allows the car to start when it reads the correct resistance. Cut the two white wires and connect in your resistor (or series of resistors) to the two wires that run to the VATS computer. This will trick the computer into thinking your resistor in your key is being read. The car will then start, and you will have permanently solved your problem.
Sometimes if you're lucky you can use a pencil eraser and clean the resistor contacts on your ignition key and get it to work. Most of the time though the wires have gone bad in the ignition switch where it contacts the resistor in the key. The procedure I described above bypasses this problem.