Very easy!!! YOU MUST HAVE ALL OF THE REMOTES YOU WANT TO PROGRAM INTO THIS VEHICLE. First, insert the key into the ignition (must be the proper key which turns the vehicle on). Then, switch the key to on postion (all the way on where all dash lights are on pre-ignition). Turn the ignition to the off position, then back on again fast. Like revving a motocycle throttle. You will do this about 3-4 times, sometimes 5. YOU MUST END IN THE ON POSITION HOWEVER. All of a sudden, the locks will lock and unlock fast about 3 times. This means the system is in learn mode. Now, press the lock button on ALL of the remotes you want to program to that vehicle. You are done. Shut the car off and test. You can't damages anything by doing this. I am a Ford nut and have done this on Windstars, Mustangs, Expeditions, Crown Vics, and the same Mercury vehicles. It is easy and if you need my help, just say so. Good luck.
