'98 Villager A/C Electrical

Air conditioning operates intermittantly. When operating blows very cold air. I checked the relay and replaced it with the FICD relay (same type just for diagnosis) found that A/C operates normally with FICD relay removed. What is the FICD relay? When both relays are in, the A/C clutch, fan motor and fast idle, cycle on and off abnormally. When A/C relay is only in, the system stays on and doesn't cycle abnormally.