Bad ground.
Yes a bad circuit breaker and a bad light switch can cause a light to flicker when its turned on. It could also be caused by loose wiring going or coming from that paticular circuit. it also could be something in the fixture itself causing. Checking for loose connections is your cheapest and first route to go.
Assuming there's nothing wrong with the light circuit itself, usually a large load on the same branch circuit (circuit breaker) will cause this. Is your refrigerator on the same circuit? When the compressor kicks on, it will drag down the voltage on the entire circuit. This is most easily noticed by flickering or dimming lights.
your headlight switch needs to be replaced. My Lincoln had the same problem, it all stems from the auto dimmer feature...replace the headlight switch (mine was 70-100 dollars) and your lights will work fine.
Sounds like the circuit breaker blowing, most likely a short in the wiring. It could also be a nearly dead battery or a loose connection.
It is possibley your alternator or battery
The circuit for the refrigerator is overloaded. The full size refrigerator typically requires a dedicated circuit.
replace your head light switch
It may cause damage to the circuit to be repeatedly used like that. Sort of like heating and cooling an iron pan.
why do my lights flicker and interior lights flicker
The Flicker was created in 1965.
Flea flicker?
Your lights may flicker because they power is really low. It is very common for them to flicker when there is a storm out.