Hi, you did not mention the year of make of this car ,I assume it is a older model, here
is what to do ,press and hold both buttons on the remote until the lights stays on
permanently ,this conditions the remote for reprogramming. You have to do both
remotes put on ignition in position 2. Than press on the lock button on the first remote
this than must blink and goes off. Than repeat this on the other remote, now the
remotes are synchronized. Turn off ignition and test remotes.