I completely replaced the grayish greenish plastic box next to the compressor aka the inverter.The hardest part was getting the prongs underneath the black box on the left side of the compressor. I used a flat head screwdriver to open it by prying it. There is actually a tab on too and hinge like mechanism on bottom. It still closes up if the tab snaps off. You will need a flashlight also.Its very dark in there.