Check the listing for details. Rotary Vacuum pump switch kit w/ relay，wire harness fit for EVP28. Condition: New. Listed at 105.00 USD. Description: The switch wire harness is not included the pump ,braket and hardware, vacuum pipe.The switch wire harness fit for GM vacuum pump and hot street vehicle 79 Corvette/64 Mustang etc.It will solve the issue that your brake pedal could be hard and you have no brakes when engine is at idle.Old mechanical type pressure switch is always have issues.The new pressure switch is at least 5 times longer life than old mechanical switch. We offer you the switch which is used to new energy vehicles.But noted keep away from heat.The working temperature is -40 to105 °C2 year warrantyIt keeps the pump from constantly running and preserves pump life.Increases idle vacuum up to 25".Features :100 % Brand New12 Volt Noted the power should be 12V.Great on street rods with radical camshaftsAll wiring pre assembled for easy installation,you could easy to replace your original pressure and relay and wire.