Yes, first check the fuses on the driver board, particularly fuses 112 and 101 to 105. If one or more is blown make sure to change it with the correct value. Don't worry, putting connectors back in the wrong place is probably more common than you think.. I've done it many times. I would think everybody has a story like this. If you don't try you will never learn!
As for the pictured wire, it is there to stop the balls bouncing back after the out hole kicker kicks the ball across to the trough. If it is not broken then it looks like it needs adjusting as it should stop on the notch in the trough wall to prevent bounce back.
Also the ribbon cables are not designed to be continuously re-seated so you may find the problem gets worse. You should consider getting a new ribbon cable. Here is one supplier
https://www.greatplainselectronics.com/products.asp?cat=52
