outwest51

hi, everyone. i am using a ls6 out of a cts-v in a swap. the a/c compressor has a green and a black wire coming out. at the factory plug only one wire plugs in the compressor and it is to the green one. when i hook up 12v to this wire the compressor clutch will not engage. do i need to ground the black wire? if so it does not look like it was from the factory. thanks for any help