I have a maker select plus with Main board version 5.1. I installed a BL touch V3.1, the LCD and Software and firmware version 4.0.6 BL3 version. I have double checked all the board connections and cannot find anything wrong. Am stumped!!! Is there an issue with BL Touch Version 3.1 and the firmware?
Have a PowersPec with BL Tough Version 3.0 (running 4.0.6) and another Maker select plus with BL Touch Version 2.0 (running the older 3.0.2 version of the firmware. Both work OK.