hi, i got a OS030ECN24TE095 order picker with a height error on display. Truck it's not moving or moving slow, I start by testing the prox. switch on the bottom of the mast, light came up but I test continuity on the harness from the connection to the traction controller and found 6 out of 11 pins doing continuity with one of the jacks on the other end. Now, another tech told me to check the pot on top by the pulley, what should I do? My experience tells me to replace the main harness but... if it's only the pot?