yes,not a prob,just remove al power from the panel mains first then open panel ,the out side sounder will go off,ignore it,pull the red wire from the battery,take off the old pir,take note of where the wires go,better still take a picture,then fit new pir wire it up,replace the cover,replace the red wire on the battery,close the cover key in your pin number
gts, February 2013