A common problem with non-working remotes are weak or dead batteries. All remotes come with batteries inside that can be replaced. If you notice your remote does not have the range it used to have this could also be the problem.
Replacing the Battery:
You will notice a seam along the edge of your remote and along this seam there is usually a break where the seam is large enough to fit a flat head screw driver. By placing a flat head screw drive into this spot you can then twist the screw driver and pop open the remote. Once open you can remove the inside circuit board and button pad by pushing from the outside buttons, so that you do not damage any of the inner parts. Once removed you can separate the button pad from the circuit board. At this point there are several different styles and situations so for now I am going to describe the steps for the most common Ford and GM remotes, but these techniques can be modified to whatever style remote you may have.
Ford, Lincoln, Mercury Remotes:
The battery is usually located on the back side of the case. It can be popped out using a small screw driver. The cover will indicate the correct way (positive/negative) to place the battery. Most of these remotes use a CR2032 button battery, but you can confirm this by looking at the numbers on the battery currently in your remote.
While you have your remote open if you see any greasy residue or green corrosion on the button contacts you can gently clean them with a soft rag or toothbrush, being very careful not to pull the contacts off of the circuit board. You can also wipe clean the inside of the rubber button insert. This will help improve the button function of the remote.
GM Remote:
These remote batteries are usually attached directly to the circuit board with a battery clip. Be very careful when removing the battery that you don’t pull up on the battery and pull the clip from the circuit board, instead slide the battery sideways out of the clip. Frequently, the connections where the battery clip attaches to the circuit board come apart or loosen, breaking the flow of power from the battery to the circuit board. The battery clips can be repaired by re-soldering the connections with a soldering gun. Replace with the same size button battery previously used, most likely a CR2032. Before closing up your remote, take the time to wipe clean any residue from the smooth side of the circuit board and button pad with a soft cloth.We sell a full line of replacement batteries at KeylessRemotes4u.com. If you are unsure of what battery you need, every one of our products lists the correct battery requirements.