how to reset security on 96 deville
try turning the key to the acc point due not turn all the way leave for 10 to fifteen min. turn all the way off take key out wait a little bit like 1 min, now try to turn it on. if didn't work try a few more times..
I believe you have GMs VATS (Vehicle Anti Theft System) security system. The visabile "chip" on the key shank is a resistance block that contacts two small wires inside the lock cylinder when the key is inserted. The most common component to fail is the lock cylinder. The small wires wear or break over time and the connection to the resistor block on the key is lost. There were 15 different resistor values used. You MUST find out which key you have before replacing the lock cylinder. Take the old key to your local GM dealer or a good locksmith to determine what key number (1 thru 15) you have. The new lock cylinder will come with a template for cutting the new key but the new key MUST have the correct resistance block "chip" on it to work. HTH. -Jim