If your vehicle is showing headlights flicker or cut out when hitting bumps, here are the most likely causes and the parts you'll need to fix each one.
If the battery terminals are loose or heavily corroded, hitting a bump can momentarily break the main electrical connection. This is a frequent issue after a recent battery replacement or jump-start where the clamps weren't fully tightened.
The plastic socket that plugs into the back of the headlight bulb can become brittle, melted, or loose over time. Vibrations from the road cause the loose connector to momentarily lose electrical contact.
In older halogen bulbs, the tiny wire filament can break but still rest against its support posts. When you hit a bump, the broken filament bounces, breaking and remaking the circuit to cause a flicker.
Headlights rely on a ground wire bolted directly to the vehicle's metal body. If this bolt is loose or rusted (often after recent bodywork or engine repairs), physical shock will interrupt the power flow.
The headlamp relay is an electromagnetic switch that powers the lights. If it is loose in the fuse box or its internal contacts are worn out, the physical jolt of a bump can cause it to disconnect momentarily.
The switch on your dashboard or steering column has internal contacts that wear out over years of use. Hitting a bump can jar the steering column just enough to break the connection inside the switch.