What game are you trying to load? If it's older games when the boots up with requires 14 button panel to active all lines. Or if you have a button panel with max bet you can hit it once to activate all the lines.
If you have a extra harness what I do is when I load up lets say Quick Hit I'll disconnect the easy select panel plug in the other harness to max bet it once. Then all lines are active.
If you don't have a 14 button deck harness or panel you would need to wire a button to the max bet pins but I'm not clear on what holes you would need to pin it too. Best thing would be to get a 14 or 9 panel.