°1.First, you have to disassemble the Hotend which is placed at the side of extruder. To do this, please follow the instruction available on our Support Center.
When a print starts or when doing auto bed calibration the head moves and touches the bed to sense position. This cable closes the circuit from the bed surface to ground on extruder PCB.
On your model this is made through the thermocouple cable, that one shielded.
Mine was like the drawings, then I had to change the hotend (v1) and then I bought a V2 extruder. Both don’t have the cable signal.
In some moment the sensing started to fail causing a plunge of the hotend on the bed. Ruining the bed.
I installed a simple cable like on the old days. The sensing was working again.