We recently received an inquiry from a customer who said the add-on car alarm system in his vehicle is an Audiovox AA-9158 system. This reference number actually refers to a power door lock interface component that was used in multiple alarm systems. Those systems include AA-9147, AA-9247, TSP-300, TSP-400, TSP-450, TSP-500, TSP-550, TSP-700 and TSP-750 alarm models.
The original remote transmitter used with these systems is Remotes Unlimited part 178-1178. It is no longer made, but there is a newer Audiovox Prestige system key fob that will work as a replacement for the original remote. You can see both transmitters at the following link:
Remotes Unlimited Part 178-1178