Troubleshooting a PlayStation 3 controller is fairly easy since the lights on the wireless device indicate what it is doing. When a light blinks quickly, the controller is low on power and needs to be recharged. A slowly blinking light indicates the controller is recharging. Fortunately, recharging the controller does not mean the fun has to stop since it can still be used while charging.
Recharging
It should be easy to verify if the blinking light is due to recharging the controller. When a controller is connected to the PlayStation 3 via a USB cable, it will automatically begin to recharge. It signals this by forming a circle pattern with the indicator lights. To continue playing while the controller is charging, just press the Home button. If the USB cord is not connected and the lights are still blinking slowly, there may be a problem with the controller. Try turning it off and restarting after a few minutes.
Pairing With The PS3
In some cases, a controller may need to be paired with the PlayStation again. This was done prior to the first time the console was used, but the process may need to be repeated to get the controller to stop blinking. To pair the devices, turn the controller and the console off. Plug the controller into the console and press the PlayStation button — the one in the center of the controller. As the controller starts to power up, push the power button on the console to turn on the PS3. The controller should stop blinking within the first minute after pairing with the console.
Rebooting PS3
Although this solution is a long shot, rebooting the PlayStation 3 may help. Turn the console and controller off. Press the Power button on the front of the PS3 and continue to hold it down until the console beeps three times and the indicator light is red. This should reboot the console. After the system reboot is completed, the controller may need to be paired with the console again.
Giving Up
If none of the other techniques stop the blinking light, it may be time for a new controller. Check the manufacturer’s warranty for the controller. If it is fairly new, the manufacturer may replace it since the blinking light may be a sign of a defective product. If the controller is older, it may simply need to be replaced.