1998 Mercury Mystique Key Programming Instructions

NOTES: Please read all instructions to ensure that you are following the correct instructions for your vehicle. You must have your key cut by a Locksmith or an automotive professional before taking any additional steps. For Mystique LS models built before February 1998, if you do not have an existing cut and programmed key follow the instructions below.

1. Insert the new key into the ignition and turn it to the on position (as far as you can go without cranking the engine).
2. The security light on the dash will flash for fifteen minutes.
3. When the security light stops flashing, turn the ignition off and then back to the on position.
4. The security light will flash for fifteen more minutes.
5. When the security light stops flashing, turn the ignition off and then back to the on position.
6. The security light will flash for fifteen more minutes.
7. After the security light stops flashing the third time turn the key to the off position.
8. Turn the key to the on position and the security light should stop flashing indicating new key has been programmed.
9. Start vehicle to test key.

NOTE: If you already have an existing key, you can use the following steps to program additional keys. All keys will need to be cut by a locksmith or an automotive professional before attempting these steps.

1. Insert the existing working key in the ignition and turn to the on position then back to the off position.
2. Within five seconds insert the new key in the ignition and turn to the on position.
3. The security light will light up for two seconds to indicate successful programming.
4. Turn the key to the off position.
5. Start vehicle to test new key.

NOTE: For Mystiques built after March of 1998, if you already have two working keys, you can program a third using the procedure below. NOTE: If you do not have two working keys for this production-era Mystique, your new key will need to also be programmed by a locksmith or an automotive professional.

1. Insert an existing working key into the ignition cylinder.
2. Turn the ignition cylinder to on (run) and back to off.
3. Remove the existing working key, and within five seconds insert a second working key and turn it on (run) then back off.
4. Remove the second working key and insert the new key before ten seconds have elapsed and turn it to the on position (run).
5. Leave it on for one second and turn it back off.
6. The security light will light up for three seconds to indicate that the new key has been successfully programmed.