Hey Rob,
I've had two of the older LM-2Ss have bad pins, so bad they blew out speakers - twice! All because I thought I did something wrong with the hook-up, not that the module was bad. Expensive mistake.
Have you connected a multi-meter to the pins to see if they are putting out any juice?
Pics of the install can help us diagnose the issue, so if you have any, please attach. The gurus on here are super helpful in these kinds of issues!!