DA left speed sensor

[Geared_Cortex]

Hi , A friend asked me to help him figure out this problem . So he get this message on the dashboard of his 2012 386 "DA left speed sensor" on and off . So left side drive axle speed sensor open or shorted . Obviously mechanic wanna change the sensor but I dont think its the sensor because he told me it comes on and off randomly while driving but also every time he is performing specific things. He runs intermodal containers and every time he is live loading very heavy recycling paper he gets the fault and every time they are taking off the container from the chassis the fault goes away . So It looks like it has something to do with some wires being shorted when the truck chassis is moving down and unshorted when it"s moving up . I unplugged the sensors to see if the fault would change and I tried plugging the left on the right sensor and right on left sensor and and also both unplugged and nothing changed . still getting the same DA left speed sensor . Am I going in the right direction ? Any Idea on where to look or what to try ?
Thanks in advance.