SDM - No Comms...... Problem

[Ninety8C5]

I just installed an HUD motherboard and other parts in my 98 Vette. Everything works fine, but when I went to check/clear the codes on the DIC, I get 'SDM No Comms' message. This has something to do with the air bag system, but the air bag light on the left blinks seven times as it's supposed to. I have a passenger side air bag shut-off switch that I had installed a long time ago and that seems to work properly also.

When I hookup EFILive and check for codes, it says no DTC codes. I reset all codes. but it's still there.

I was wondering if anyone has come across this problem and/or knows how to fix it. :help2:

Thanks!