[Richard]

The boards require 12v signals from the tstat for fan and compressor functions. Thats the challenge. I have measure the tstat response on all wiring. I have made circuit board with amazon sourced relay boards and also arduino based boards. Both are backups to the original SCS boards. If you will find “adding relays to SCS boards” you will find info on bulletproofing the original design. Keep in mind this only applies to the SCS basement units. It does NOT apply to Dometic basement units or any roof top unit.