The key looks like it has a chip on it, but it is a resistor. Use an ohm meter and read the resistance by touching one lead of the meter on each side of the resistor. There are keys for sale on E-bay and the resistance will determine what code key you need. Take the blank key and have it cut using your existing key and you are ready to go. If you don't have an existing key, you will have to replace the ignition cylinder.
If I understand correctly you lost the key and the ignition still works. If this is true go to a dealer they should have a replacement key to buy.
you will have to replace the complete ignition switch with a new one.
You will more than likely have to get a new ignition and key for it.
Go to your GMC dealer they can get one
According to my owner's manual you must contact a BMW dealer to replace the key.
If you don't have the code, you will have to replace the lock cyl. They pop out if you know the procedure (and come with keys).
Don't replace anything. The dealer can make you new keys by using the Vin # on your vehicle.
A Mazda Dealer's Parts Department can cut a new key from the car's VIN number.
There is a lock ring on the inside of the dash where the switch connects. You need to remove this lock ring to remove the switch from the dash.
Lost ignition keys for newer vehicles can be obtained from the vehicle dealership. Lost keys for a 1978 Honda Accord will require the replacement of the ignition.
Ford Dealership should be able to help. If not you may have to replace the ignition and steering column .$$$.
A dealer can look up the ignition codes to make a key if one needs to be replaced on a 1992 Olds 98. A locksmith can also help but the ignition cylinder has to be removed.