Hope it's okay I put this here, not sure if this is LS1 only.

I had a SES light the first day I had my car put back together, turned out I forgot to connect one of the electrical connectors to the left oxygen sensor. But I also got "AC Clutch Relay Fault" and "AC pressure fault". Now, I have had my ac deleted all but the compressor for a while now and didn't get any codes then. When I did head gaskets recently I deleted the AC box and put a firewall cover in place of it, but kept the vacuum line to the check valve for Defroster operation. After doing this I now have this code, but only in history codes. I have been able to delete history codes in the past but cannot delete any of the 3 codes I mentioned. Why can't I clear these? And if the A/C codes come back, how can I stop them?

By the way, the scanner is an AutoXray EZ Scan OBD-1 Scan Tool.