Jono 02 stang

Iinstalled adiablo programer when I first gotmy mustang one year ago and put the tuner back in the box and put it away. I just installed a set of 3.73s and wanted to set the gear ratio on the speed meter, so I put the diabloback on the car and nothing happens. The tuner won't turn on. The tuner is notbroken because whenIPlug the power cord for the program updates on the computerit works fine. Can there be a loose connection under the dash or has anyone had this problem before?