Nice cab, did you get this from Mini?(David). I'm pretty sure this was his cab.
As others have said the lights should flash when you reach the criminals. The bulbs would be the first place to look. After that look at the voltage driving them, they are powered by a seperate transformer at the bottom of the cab. It should be putting out 13V. If that is present then you might have a PCB fault as thats where the lights are driven from.
Ref SCI - I have this in my Chase HQ cab and it works fine. I wired the gun control into the start button at the JAMMA connector to keep it neat. (ok its not ideal but it keeps the cab looking original with no nasty buttons on the CPO). Other differences I can think of off the top of my head are that Chase HQ cabs are wired mono and SCI PCBs are 2 channel. I just rewired my cab so that both games are now stereo. I think Electrocoin were just saving money by wiring the cabs in the way that they did BITD. I'm pretty sure most of the other connections are the same.
Cheers Dan