Keyless entry, considered a luxury until the mid-to-late 1990s, is standard on most new vehicles. Keyless entry remotes are known by many names, including key fobs, clickers, door remotes and remote keys. After a period of time, your keyless entry remote may stop working. This is due either to a discharged battery or a faulty remote. Whichever problem your remote has, you shouldn't have trouble fixing it or replacing the remote.
Try replacing the battery before acquiring a new remote. On average, keyless remote batteries last two to three years. Pry open the remote with a coin or a flat-bladed tool, remove the old battery and bring it to an electronics store to match it up with a new one. It's more likely the battery is dead than the remote is faulty--although remotes can eventually fail.
Examine the back of your remote to find the ID number. Each manufacturer has a different ID number on the back; it's not always the same between car models (for example, not all Mazda remotes are compatible with a Miata).
Purchase a replacement remote. You can always purchase a new remote for your vehicle from an authorized dealer, but you may also be able to purchase a used one from another source. Several online retailers sell keyless entry remotes; you can also find them on eBay. Match up the remote ID with your current remote to make sure it's compatible.
Install a new battery in the replacement remote, if needed. Pry open the remote halves and insert the battery. Line up the "positive" and "negative" symbols according to the internal markings.
Follow the manufacturer's procedure to program the remote. The programming procedure varies greatly between vehicles, but most are user-programmable. Some remotes, however, require a dealer scan tool to be programmed. You can usually find programming instructions in your owner's manual. If you can't find them, see the Resource section for a free website with comprehensive programming instructions for different vehicles. If you cannot find the instructions for your vehicle, it probably requires dealer programming.
