I own a 93 sc300 it was missing the stereo and ther is alot of plugs back there... the AC control unit is there but wont turn on... I checked the fuses and relays, everything is good, also a couple of cables have from the ac unit harness have power so I dont know what else to check... I went to the local pickapart and noticed other vehicles had a little 2 prong realy box in the area where the ac unit is at and my car is missing it. would that be the missing part to make it all work?