The LS1 switch acts as a high and low pressure switch and was screwed into the drier when I received the motor and tranny. It doesn't work worth a crap on the high side. I kept popping the valve on the back of the compressor instead of the switch taking it out like it should. The 3 wire switch will take the compressor out between 28 and 30 psi. I just went through this and finally got my pressures right.