I had the same problem recently with my Lancer. I had to get a new remote as the aftermarket I had was dogey. (I changed manufacturers, but my remote was still programmable with my central lockng and alarm system) Thing is, you can't just buy any remote, it has to be compatible with your current system.
Your central locking system should have come with a remote, but anyway, check out which system it is (there should be a tag somewhere along the system's wires telling you who it is with), then contact the manufacturer and ask if the make and model of the remote you bought is compatible to your system. The manufacturer should have instructions as each brand have their own unique programming instructions - they may charge a small fee to give you the programming instructions.
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