I have a 2001 Pontiac firebird, the interior lights flicker, In sequence with the headlights when the car is running, 24/7.

Hi, I have a 2001 Pontiac firebird, and the interior lights flicker and pulsate in sequence with the headlights, doesn't matter if it's hot or cold, or when it is, when I crank the car, they do it, now if I have the car shut off and lights on, nothing flickers. I have no idea what could be causing it, maybe the alternator going bad? Or even a bad connection. Maybe you guys know, thanks! -Trent.

My car has 93400 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi Trent,
It sounds like you may have a voltage regulator that may not be allowing the alternator to maintain a consistent charge. You may have a failing voltage regulator that could be allowing the alternator to supply too much or too little amperage to the battery resulting in the battery never maintaining a consistent charge as it is designed to. The voltage regulator is a unit that regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. A common sign of this is usually the acid inside the battery boiling causing the battery to swell. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

A failing light switch, either the interior dimmer or the headlight switch, should be considered if you have flickering lights on your vehicle. In some rare situations, just replacing a worn switch may solve the problem, especially in vehicles with excessive mileage or older vehicles.
It could be a loose connection in just that circuit, or the circuit might be overloaded. If the lights are flickering throughout your house, you could have a more serious issue with all of the wiring. It could be an issue with the electrical panel or the main connections to your home.
If you see your car lights flickering while driving, it`s most likely due to a battery that`s failing. If the car battery is normal, there are other trouble areas that may be responsible for the issue. Whether it`s the battery or something else, it`s imperative that you have the problem fixed ASAP.
Another common symptom of a problem with the dome light bulb is a flickering dome light. If the dome light bulb filament wears out or becomes damaged this may cause the dome light to flicker rapidly when it is turned on. The dome light will continue to flicker until the bulb completely fails.
ROUTE CAUSE OF FLICKERING

More often than not, your LED lights flickering is caused by the power differences between what your car emits, and what the LED bulb requires to run. You also have the differences in the current that runs through your car and what the LED bulb picks up on.

Bad bulbs or fuses

If the vehicle battery isn`t the reason for your flickering car lights, you might be looking at a failing light bulb or a bad fuse. Light bulbs are an easy and quick fix and present an opportunity to upgrade to new LED bulbs.

Even if the flickering seems harmless, it could be a sign of a more serious underlying issue with your electrical wiring that could present a dangerous fire hazard to your home. Particularly if the flickering increases or changes in any way, call your electrician for an inspection just to be safe.
If the flickering stops, it`s quite likely just a loose connection. If the flickering persists (and a dimmer has been ruled out as the cause) then a new transformer may be required. An alternative solution is to do away with 12V MR16 lighting altogether and upgrade to a mains voltage LED downlight.
In most cases, a blown interior light fuse means that there`s some kind of short somewhere in the system. It may be a permanent fault, or it may be temporary, but the only way to know for sure is to replace the fuse and see what happens.
When lights flicker, it`s the result of a fluctuation, often a reduction, in the circuit voltage, which makes the lights dim for a brief moment. However, these rather abrupt changes from low voltage to high can damage your electronics, and sometimes even cause electrical fires.
If you notice any flickering, be sure to check your battery before you end up stranded. Similar to dimming headlights, these flickering lights are a sure indication of a failing car battery.
3 flashes means caution there is something ahead to watch out for (cops, deer on road, down tree, etc.) at an intersection flashing your lights it means that your giving the other motorist the right of way or letting them cut in front of you.
Why Do All Dashboard Lights Turn On While Driving? When all your dashboard lights turn on at once, it most commonly indicates an issue with the alternator or the charging system. It is common for all the dash lights to come on with no alternator output; low voltage can cause unusual electrical issues.
3 flashes means caution there is something ahead to watch out for (cops, deer on road, down tree, etc.) at an intersection flashing your lights it means that your giving the other motorist the right of way or letting them cut in front of you.
Why Do All Dashboard Lights Turn On While Driving? When all your dashboard lights turn on at once, it most commonly indicates an issue with the alternator or the charging system. It is common for all the dash lights to come on with no alternator output; low voltage can cause unusual electrical issues.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

I have a 2001 Pontiac firebird, the interior lights flicker, In sequence with the headlights when the car is running, 24/7.
ANSWER : Hi Trent,
It sounds like you may have a voltage regulator that may not be allowing the alternator to maintain a consistent charge. You may have a failing voltage regulator that could be allowing the alternator to supply too much or too little amperage to the battery resulting in the battery never maintaining a consistent charge as it is designed to. The voltage regulator is a unit that regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. A common sign of this is usually the acid inside the battery boiling causing the battery to swell. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle.

Car won’t start. The check engine light, battery light, and oil change light are coming on. I tried jumping the car and nothing happened. Why won’t my car start?
ANSWER : Hi and thanks for contacting Your Mechanic. If sometimes your vehicle will start with the new alternator and sometimes it won’t, then there is a loose connection in your charging system. Check all of the wires to the alternator and to the battery. Make sure that the battery cables are clean and tight. Make sure that the wires to the starter are clean and tight. A loose ground to the ignition system will cause the vehicle to not crank over. Check all of the ground wires from the battery to the starter. Make sure that they are clean and tight. If you need further assistance troubleshooting your no start situation, then seek out a technician, such as one from Your Mechanic, that can assist you.

Lights are flickering. Interior and exterior. What can it be?
ANSWER : Check the ground wire from the engine block to the chassis. It may be loose causing a loss of power return to the battery making the shortest path to the battery. Also, check all of the ground wires on the chassis to the cab and make sure they are all tight. A loose ground wire will cause the circuits to work and shut off temporary when the wires are moved around. If you need further assistance with your lights flickering, then seek out a professional, such as one from Your Mechanic, to help you.

First, the fuse 19 keeps blowing. When I hit the brake pedal my dash lights up. The third brake light acts like a running light.
ANSWER : Hi there. Check the wiring on the vehicle to the tail and brake lights. There is a cross short that is causing the lights to blow the fuses and make the tail lights brighter than normal. If you need further assistance with your electrical issues, then seek out a professional, such as one from Your Mechanic, to help you.

Battery and oil light come on when trying to start car, take keys out try again car starts no problem and lights go away
ANSWER : Of course, don’t switch gears without being fully stopped, unless your Owner’s Manual or the manufacturer has alternative advice. However, the gear shift issue has no relation to the no-start problem you are describing. Inasmuch as you only have 6,000 miles on the car, the "constant on and off" that you believe has occurred is meaningless in comparison to the expected total vehicle service life. That is, assume what you perceive as "constant on and off", during merely 6,000 miles, might be equivalent to using the car "normally" for three years. A new car should be trouble free for at least 5 years, unless there is a defect, so your "constant on and off" is not a causal factor for any fault on the vehicle. What you might have is a defect in the ignition switch, or perhaps the immobilizer system, but if the problem is not in the switch itself, clearly there is an electrical problem.

If your vehicle is under warranty, by law the dealer MUST repair the issue you are describing within a prescribed time frame and number of "attempts", otherwise the dealer will run afoul of Federal and state Lemon Laws that give you very specific rights, and recourse (contact an Attorney; we are Mechanics, NOT attorneys). Consequently, if the vehicle is still under warranty, to save yourself money do be sure to seek a resolution from the dealer. If the vehicle is not under warranty, obviously a certified Mechanic from YourMechanic could identify the electrical fault and resolve this for you. If you want to go that route, please simply request a no start diagnostic -electrical system and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

No dash lights, back right tail light is out, no parking lights. Brake lights work though as does head lights.
ANSWER : Hi there. In many cases, when you have electrical problems like you’re describing, it’s caused by multiple electrical component failure. It’s likely that a few electrical relays are not working; especially if you have systems that utilize the same components (such as your brake light and tail lights). I would recommend having a professional mobile mechanic come to your location to complete an electrical problems inspection first, so they can pinpoint what is damaged and recommend the right repairs.

My car stalls at times, yesterday the car shut off at a red light. I turned car off then back on now engine light is on.
ANSWER : This may be a result of a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. Since this valve is controlled by the vehicle’s computer, it will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your idle air control valve.

2012 equinox reduced power light engine light and traction light came on. Lost a lot of power got home and all light except engine
ANSWER : Your car has what is called a "safe mode" that will be engaged by the computer when it detects that something critical has gone wrong related to any of the major components in your engine chassis or power train. This may be related to a number of things, most of which should have been registered in the computer when the check engine light came on. I recommend having an expert from YourMechanic come to your location to inspect your check engine light and diagnose any codes registered by your vehicle’s computer.