It is possibley your alternator or battery
why do my lights flicker and interior lights flicker
The alternator may have a faulty rectifier or faulty voltage regulator
You may see the headlights and dash lights flicker at an idle. You may hear unusual noises coming from the alternator when the engine is running.
If the lights flicker when the vehicle is running, the alternator is on it's way out.
You may have a pull on your batt, or a surge.
Your lights may flicker because they power is really low. It is very common for them to flicker when there is a storm out.
Make sure the battery cables are clean and run a good ground from the body to the negative battery cable flickering bright or dull? do they flicker only when motor is running? if they flicker only when the motor is running and are full brightness it is probably voltage regulator.i need more info on problem
bad wire connections inside the fan
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.
Why do interior lights stay on when engine is shut off on 2001 Lincoln Continental car?
Bad ground.
If all of the lights flicker I would check for a loose or corroded ground. If only 1 light flickers then check to see if the bulb is properly plugged in to its socket, or if there is dirt, corrosion or rust causing a poor connection.