2004 Mercury Grand Marquis Owner Guide 3rd Printing - Page 85
2004 Mercury Grand Marquis Manual
Page 85 highlights
Locks and Security 5. Within twenty seconds of removing the second coded key, insert the new unprogrammed key (new key) into the ignition and turn the ignition from 3 (OFF) to 4 (ON) (maintain ignition in 4 (ON) for at least one second). This step will program your new key. 6. To program additional new unprogrammed key(s), wait at least 20 seconds and repeat this procedure from Step 1. If successful, the new coded key(s) will start the vehicle's engine and the theft indicator will illuminate for three seconds and then go out. If not successful, the new coded key(s) will not start the vehicle's engine and the theft indicator will flash on and off. You may repeat Steps 1 through 6. If failure repeats, bring your vehicle to your dealership to have the new spare key(s) programmed. 85 2004 Grand Marquis (grn) Owners Guide (post-2002-fmt) USA English (fus)