It's gonna be a few week process at least but I will get it looking/playing good.... I'm on a mission

I'm actually finishing up my version 2.0 pinball cab right now as well so I'm kind of bouncing back and forth between the two projects right now.
Need some input tho guys on my attempted ketz shifter hack. I found a youtube video where a guy shows how to wire the three microswitches in the kezt to an ic decoder and get four separate outputs for wiring into my A-pac. I followed the wiring diagram he posted and it doesn't seem to be working. With the thing powered up with 5vdc, shifting through the various gears does not ground any of the output pins.... here is the wiring pinout I followed:
74LS138 pins:
1 - Shifter Grey/Red wire
2 - Shifter Grey/Blue wire
3 - Shifter Grey/Yellow wire
4 - GND
5 - GND
6 - VCC
7 - neutral output (tie to 12)
8 - GND
9 - 2nd gear output
10 - 1st gear output
11 - NC
12 - neutral output (tie to 7)
13 - 4th gear output
14 - 3rd gear output
15 - NC
16 - NC
Has anyone done this hack? I notices the picture on the video appears to show his ic wired up differently that the posted diagram (he has a wire that appears to be grounding pin 9 visible in the video???). Help dudes!! I need this shifter working for some Daytona action!!