Hello
If the sensor does not work please try moving it a little bit closer to the magnet, replace the batteries on the remote, clean the sensor as per owners manual instructions. Contact your dealer if you need replacement parts for your D5. This motor is 24 months warranty covered, you can register your D5 gate motor online at www.centsys.co.za which will assist you in keeping a record of your date of purchase or installation, serial numbers, etc.