I bought the mazda 2nd hand and it has front and rear parking sensors and also a small switch inside the car to turn them off manually.

Im wondering if anyone has any problems with them.

My battery has gone flat 3 days running, I had RAC out today to start the car and they did a battery test. While they connected the tester it kept picking up that something in the car was switched on even though the key wasnt in the ignition and everything was switched off. Because I park next to a wall if the ignition is on then the parking sensor goes off, when I manually switched it off and he attached the battery tester again it didnt pick anything up 2nd time round.

I am wondering if maybe the sensors arent actually automatically switching off and thats why my battery is going flat. The battery tester said that the battery is good and therefore it doesnt seem as if its because a new battery is needd.

Could it be the sensors Or can anyone think of anything else that may be making my battery flat?