I have an Anet A8 with Marlin Firmware 1.1.9 and I installed a BLTouch sensor. When I start the system the BLTouch does its self test (extend and retract the probe twice) and then lights up red. When I "Auto Home", it homes X, then Y and then extends and retracts the probe and moves up a few millimeters. Then with the probe retracted it moves down until the nozzle crashes into the table. The same happens when I select "Level bed".