Outdoor Pir Sensor

Yesterday I tried to know where my light switch is for external security that works with a PIR sensor. This has already been integrated into the house I bought and I had to experiment. I first "on" light by putting my hand on the PIR, then I switched different switches on and off until I work that is light with all. I turned on the light / sensor back again, but since then he has not cut at all.

It used to be set to be out EXCEPT when the movement was detected during the night. Now it is just on permanetly.

Do I have something broken - do I replace the sensor? Or is it a matter of adjustment.

I tried to put out for several minutes, then on again, but it does not help.

Probably a switch to two lanes.

PIR units go wrong, as everything is "the man.
Replace the Piru and should solve the problem.