I have a MF 1759 that I cannot get to show MPH on the display. I have removed the 5amp fuse, then turned the switch on. I then scroll down to "units" and long press it til it beeps and"mph" shows up. Then I long press it again til it beeps and it says "set". I turn the switch back off and reinstall the fuse. I turn the swit h back on and the display still says "off" as it always has. What am I doing wrong??? Thanks for the help!!!