Upon arrival tech found blower running at gas pack but receiving no Y call. Tech removed thermostat and jumped Y circuit and still received no call at unit. Only 4 wires on old side of splice, used white wire in place of Y wire for testing purposes. System came on properly and cooled with white wire confirming a break within Y circuit. Sent estimate on thermostat wire replacement as well as thermostat due to its age. Customer will make a decision for approval. Also need to get quote on CMA.