Clutch Safety Switch
The clutch safety switch, sometimes called a clutch start or interlock switch, is an electrical switch connected to the engine’s starting circuit.
The clutch safety switch prevents the engine’s starter motor from cranking the engine unless the driver applies the clutch pedal. This eliminates the chance of cranking the engine with the transmission in gear, which could cause sudden vehicle movement, especially if the engine starts. In some cases, the clutch safety switch also serves a secondary purpose -- it disables the cruise control if the driver applies the clutch with the cruise control engaged.
Not all cars are equipped with a clutch safety switch, so check your owner’s manual for mention of this safety device. Problems with the clutch safety switch may include a no-start condition, starting with the clutch released and the transmission in gear, and inoperative cruise control. If you suspect a problem with the clutch safety switch or its adjustment, consult a professional service technician.