There are vehicles with alarm systems but without a working siren which makes it difficult to program a remote. Most systems programming involves choosing specific channels and then assigning a button functions to them. You'd know which channel has been selected during programming or if the system has entered programming mode by listening to chirps made by the siren. Without getting any indication, it can be difficult to complete the programming process.
Here at RemotesAndKeys, we sell valet buttons which you can plug into the blue port of your aftermarket alarm system so you can activate the programming mode. We also suggests that you check if there's a valet switch or button installed with the system before you attempt to program a new remote. If you're looking for a valet switch, aftermarket remote, alarm system, etc. you can chat with us or call (386) 586 3650.