مفتاح قطع الوقود بالقصور الذاتي مُفعَّل

The impact switch that cuts fuel delivery after a collision, tripped so the vehicle will not run. It exists to stop the pump feeding a leak after an accident, and it is designed to be sensitive — which is why it also trips on a heavy pothole, a kerb strike, or a knock while the vehicle is being moved in a workshop.

The symptom is a vehicle that cranks and will not start, with no fuel pressure and often no pump noise at all. It is one of the few no-start faults with a free, instant fix — the switch has a reset button — and it is worth checking before any diagnosis of the pump or its circuit.

Its location is the practical difficulty, since it is deliberately tucked away: a footwell kick panel, behind a trim panel in the boot, or under the bonnet against the bulkhead, depending on the vehicle. If it has tripped for no obvious reason, check the vehicle's recent history — and if it trips repeatedly, the switch or its mounting is faulty rather than the vehicle being unlucky.