John,
First of all, I'm assuming NONE of your A/C units are operating. If they're pushing warm air, or only one is not functioning, the KIB unit may not be the problem.
To reset, you need to cut all power, both 12V DC and 120V AC. In the main circuit breaker box, turn off the main 50 amp breakers to cut 120V AC. The use the soft battery cutoff switches in the control panel to cut off all battery power. Press each switch one time only. The light in the switch may take a minute to go out. If you press multiple times, it'll cycle off and back on.
Reset all power after 30 seconds and see if the KIB function is restored.
If not, you'll have to take a look at the components. The KIB HVAC module is shown on page 9 of the
KIB Multi-Plex Control System V2.0 user guide.