Nissan Nv250 Reverse Light Switches Available Here. Your reverse lights are important safety features on your vehicle and must work properly. If either or both of your lights are always on, never on, or come on sporadically, your reverse light switch might be malfunctioning. These switches are what activate your reversing lights when you shift into reverse. If you drive a lorry, they also activate the warning buzzer when you back up. If a switch fails while you’re driving down the road, you’ll not only drive other motorists bonkers, you may even cause an accident. Reverse light switches are prone to shorting out. If they do, that’s what causes your reverse lights to flicker or intermittently go on and off. This, in turn, causes the bulbs to burn out much more quickly than normal.