It’s fairly easy to program a replacement keyless entry remote. Even better, what if you have two vehicles the same make, they use the same remote! Also when the battery goes bad remotes may require to be re paired with the vehicle.
If you get a new keyless entry remote (key fob) or change the battery in your remote you may need to reprogram your vehicle to accept the remote. This procedure works for a lot of 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, and some 2008, and 2009 GM (Chevtolet and GMC) vehicles.
If you get a new remote or change the battery in your remote you may need to reprogram your vehicle to accept the keyless entry remote or key fob. This procedure works for a lot of 1998-2008 ford vehicles, see below for vehicles that the procedure works on and vehicles that use a slight variation on this procedure. I attempted to get this list accurate, I apologize because mistakes were probably made.