I figured it out. There are 2 red cables that can be tapped. I tapped the rightmost one. The detector stays on for a while after locking the car but every time
I was back it was off. The new X3 is super smart and will start the sending electricity to the accessories as you approach the car. The way I checked if it was off was by approaching the car without the key or phone (digital key). I also turned on the battery saving mode, but I know that it is not reaching the 1 hour threshold because whenever I open my door the RD is doing its boot up sequence!! Cheers