Inertia sensor switch

In a vehicle having a longitudinal direction,

• an inertia sensor switch comprising:
• a housing of an insulating material fixedly secured to the vehicle;
• a fixed electrical contact plate mounted securely to the interior of the housing, the fixed electrical contact being connected to one of two electric wires;
• an electrically conductive mass selectively abuttingly engageable with the fixed electrical contact plate;
• and
• a U-configured resilient strip having one leg secured to a portion of the housing and other leg fixed to the mass, the U-configured resilient strip being made of an electrical conductive material and serving as an electrical path between the mass and other one of the two electric wires, the U-configured resilient strip resiliently biasing the mass to an initial inoperative position that is spaced from the fixed electrical contact plate rearwardly in the longitudinal direction with respect to the vehicle;
• in which the U-configured resilient strip lies in a plane normal to deceleration due to up and down vibration of the vehicle, the U of the U-configured resilient strip being open to a transverse direction relative to the longitudinal direction.