Rotary 3 Speed Blower Switch WITH Plastic 'FAN' Knob. Has 5 Spade Terminals And A 1/4" 'D' Shaft For The Knob.Threaded Shaft Length Approx. 3/8" (Body is Approx. 1" X 1" Square, Threaded Shaft Diameter Is 7/16" ). The 'H' , 'M' and 'L' terminals are for fan speed leads..The 'B' terminal is the power 'in' terminal, while the 'C' terminal is for the clutch, thermostat, trinary or binary switch depending on application. There is NOT a ground terminal on the switch. The motor and /or switches are normally internally or externally grounded. Has Off/ Low/Med/High Positions, 12 VOLT, 25 Amp. Rating. Replaces: Four Seasons 35702 MEI 1151 Honda 00091-31511 Red Dot 71R1150 / RD3646 Freightliner INM2G754A Kenworth 71R1150 Mack 4428-2T754A Delco 15-50180 Everco H755 Santech MT1355 Universal SW 1000c. [NOTE] THIS DOES NOT MAKE YOUR 1 SPEED MOTOR A 3 SPEED !! THIS IS FOR MOTORS THAT ARE 3 SPEED ALREADY!!! THESE ARE FOUND ON MANY UNDER THE DASH A/C UNITS