Upon arrival tech was informed previous company was out and replaced contactor but system was still showing a failed contactor error. Tech began inspecting system and found contactor was wired incorrectly, corrected wiring and error code for compressor proving appeared. Found error code was due to discharge pressure switch being stuck open. Tech bypassed switch and tested system and it began cutting out on low pressure switch in heat and cool mode. Tech performed leak search and then added nitrogen to build a higher pressure but was not able to locate a leak. Current standing pressure is at 275psi with nitrogen and Freon charge in system. Customer would like to perform another leak search before moving forward with any repairs.