Volvo break demand sensor

Volvo VNL Break Demand Sensor 

2 identical sensors, one in the dash left from the break pedal. Another one is under the truck on ABS module under passenger side. If you change both sensors and the problem doesn't goo away (after calibration), then replace pig tail under the cab (dirt damages it). 

This video shows how to replace the sensor in the cab:

https://m.youtube.com/watch?v=tIHqz0cwHI4

Cable tag E1

Price at Volvo dealership:

Sensor ~ $150

Pig tail ~ $50