Why won't my 1999 Saab 9-5 ACC power up after I tried to fix the pixel problem?

After successfully repairing the SID unit using foam tape to add pressure to the ribbon cable, I tried doing the same thing to the ACC unit but now it won't power up when I put it back in the car! I tried resetting it (off and auto buttons simultaneously) and also nothing is blocking light sensor, but still absolutely no power or hint of life! While taking it apart and putting it together, I didn't have anything unusual happen (like dropping it, ripping the ribbon, etc.) so I have no idea what might have gone wrong? Any ideas or suggestions?