Upon arrival tech found condensing unit not running on downstairs system. Tech removed thermostat faceplate and found 0 volts at R circuit. Air handler is located in crawlspace. Tech opened crawlspace door and found large snake at crawlspace entrance as well as multiple snake skins. Tech placed crawlspace door back and was unable to further diagnose system due to snake. Informed customer and recommended having pest control come out and taking care of snake issue. Tech stated to call back once taken care of so we can schedule to come back and further diagnose system. Customer agreed. Tech suspects blown fuse and most likely a low voltage short. Send tech that does not mind snakes if available for next visit. Collected $87.00 plus tax per Housecall fee.