This is not a 'guess what it is' forum Make and model would have helped. you could be referring to a go-cart with doors.
Try this from my Peugeot book what to do after replacing batteries in remote key
1. Insert key in ignition turn it on but don't start the car.
2. Turn the ignition off leave key in ignition.
3. Turn ignition on and immediately press the lock button.
4. Turn ignition off remove the key and see if it helped.
Bob UK
January 2013