We know you must be thinking that there is something seriously wrong with your car if your car won’t turn over but your lights come on. Just because the electrical components seem to be at least partially working in your vehicle, doesn’t mean that you have everything figured out.
Since there are various systems within the car, the transmission, engine, and other issues could be completely separate from any lighting components. Let’s check out the top reasons of what it means when your car won’t turn over but lights come on.
If your car won’t start buthe the lights work fine and the radio is turning on, then it could be one of a few different problems. One of these issues is the potential of a dead battery.
The reason why the radio, the dashboard lights and warning lights, the headlights, and other electrical components can obtain power while the engine cannot, has to do with the current amount of power each device requires and something that is interrupting the path of flow – in this case, directly to the engine, preventing the car from turning over.
Bad Battery
The most common reason cars don’t start is a dead or faulty battery. Even though most cars run on gasoline, they all require electrical power to function. The starter that cranks your engine to start requires an electrical signal to fire.
If something’s wrong with your battery, your car engine won’t turn over. Other symptoms may indicate a dead battery, but checking whether your engine turns over at all is a good first step.
The good thing about dead batteries is that you may not need a professional to get your car going again. Jumping a car battery is typically straightforward, as long as you have jumper cables and another power source.
However, a battery jump may just be a temporary solution, and new batteries can be expensive, so it’s best to always take good care of your battery.
Symptoms of a Bad Battery
There are some telltale signs of a bad battery. Look for these issues when your car is hard to start, starts inconsistently, or there’s no sound or light on when you hit the ignition.
- Dashboard and interior lights are dim
- Windshield wipers are slow or barely move at all
- Electric windows slowly open or close
- Battery and/or cables are corroded
- The radio won’t turn on
- Swollen battery
You could have a bad battery if the cranking of the engine is sluggish, there’s no sound or interior lights when you try to start the vehicle, your car starts inconsistently, or you can start it with jumper cables but the vehicle will not start again after being shut off. A loose or corroded connection can also cause issues.
Bad alternator
A bad alternator can lead to a dead battery. The alternator recharges the battery and keeps the car’s electrical systems running after the car has started.
If you have a bad alternator, you don’t necessarily have a bad battery, but you certainly might not have a functioning one. Any bad alternator should be replaced, so be sure to look out for any signs of a bad alternator.
How to Tell if Your Alternator is the Problem
While it can be difficult to tell if your alternator is creating electricity without a lot of specialized tools, there are some signs to watch for:
- Trouble starting the vehicle
- Frequent stalling after you’ve started your vehicle
- The squealing sound coming from the engine that gets louder when you use the heater or sound system (this may be your alternator bearings)
- Interior and exterior headlights that seem to dim and brighten
- Check-engine or battery indicator light illuminated on your dashboard
- The vehicle immediately stops running after a jump start
Here’s a quick way to diagnose your alternator: Get the vehicle started (if possible). Then turn on your radio and tune to a low number on the AM dial. Finally, rev the engine. If you hear a whine or the sound goes fuzzy when you hit the gas, your alternator is probably failing.
Bad Fuses, Fusible Links, and Ignition Switch
If the battery is in decent shape and the power is not dead, then you might want to check for a blown fuse or a fusible link. Make sure you check your car’s manual to find the location of the fuse box, and then see if the fuse or metal wire is damaged.
If the metal wire in the plastic is damaged or disconnected completely, then a blown fuse might prevent power from getting to the starter relay.
If you do this check and you determine if the fuse is in good shape, then the real problem is the car’s ignition switch and it not working correctly.
Contrary to popular belief, the ignition isn’t’ actually the mechanical hardware that you put your key into when you are trying to start your car. It is actually the electrical switch inside that your key touches when the mechanical part is inserted into the ignition.
In some situations, the ignition switch can actually only give power to the electrical components within the car and avoid the engine starter.
There are key signs to a failing ignition switch or bad ignition. One sign is that the car can stall while driving, meaning that the ignition might cut off power to the fuel systems, meaning the engine would stall.
The second sign of a failing ignition switch is that the ignition switch might constantly be in the “on” position, which can consistently give power to the fuel pump and the ignition system when in the cranking position, which can overload the sensor. In addition, if it fails in the “on” position, it can cut off power.
In addition, another sign of a failed ignition switch is when you notice problems with turning on the accessories in your car. When you insert the key and turn it into the on position, the accessories might not power on. If this is the case, then you will have ignition problems, fuse issues, and wiring issues.
Now that you know the signs of a broken ignition switch, you can see how this problem would cause you to wonder what it means when your car won’t turn over but your lights turn on.
Diagnosing and remedying a broken ignition switch is unfortunately a bit more complicated than checking for a broken fuse. However, the good way to check is that if the instrument panel and dashboard lights do not turn on when the key ignition is moved, then the problem is most likely with the ignition switch.
If you have a car with manual transmission, a faulty or damaged clutch pedal sensor can prevent the engine from turning over, while still allowing the lights to turn on.
Bad Starter
Another reason that your car won’t turn over but your lights come on is that the starter is not working correctly. The starter in your car is the electric motor tha cranks your engine in order to turn on your car.
The entire system of the starter consists of the motor, the solenoid, which takes the battery power and delivers it to the motor, and the flywheel.
In order to start your car, you need a high current. This enables your engine to have enough power to start the car properly. Whenever your car will not start and the battery is charged, the starter motor is usually the culprit of the issues.
There are a few signs that show the common starting problems, which are all related to the starter, what it means when your car won’t turn over, and why your lights will turn on.
First, the starter can crank but the car will not start. This is usually due to battery failure, which is due to something being left on and causing the battery to drain. It could also be due to poor connections, damaged battery terminals, or a bad or dead battery. Sometimes, this could even be due to the starter, with the control terminal becoming corroded.
Another sign that there are starter problems and a reason for why your car won’t turn over but your lights will turn on is that you have to jiggle the key to start the car. This shows you have a bad ignition switch and the solenoid is not being activated.
In addition, the car might start when it is in neutral, but not when it is in park. The neutral safety switch in your car usually prevents the car from operating when it is in neutral or park, but if this occurs, you have a damaged neutral safety switch.
Lastly, another sign of an issue with the starter in your car is that the lights go dim when the car is first started. If you test your battery, check to see if the issue is with the car starter control circuit.
This could be due to the starter relay, ignition switch, or neutral safety switch. Any of these reasons could cause damage to the starter and prevent your car from turning over, but letting your lights turn on.
If you find that your car starter is the issue as to why your car wont’ turn over but your lights come on, then you might need to replace the starter in your vehicle.
This can be done by a mechanic if you are not certain about what to do, but if you have the tools and knowledge, then you can save some money by doing this replacement yourself.
First, turn the ignition and remove the negative battery cable from being attached to the battery. Then, remove the positive cable, which is the large one that runs to the battery.
After you have removed the cable, disconnected the bolts that hold the starter to the block. Once the starter is removed, remove any other supporting brackets that are keeping the starter in the right place.
Then, disconnect the bolts holding the starter, using a lubricant to help grease and remove the tight bolts.
Now, remove the starter from the car. Install the new starter on the block and reattach it with the bolts, reconnecting the battery cable to the starter. After this, tighten the bolts to the starter and reconnect the negative cable.
Engine Cranks but Won’t Start
Low Compression
In order to start running under its own power, an engine needs four essential things: air, fuel, compression and spark. An engine with low compression can be difficult or impossible to start, and it means seals and gaskets could be leaking in the engine.
You may need things like new valve seals, new piston rings or other components replaced so that the engine can withstand the intense pressure it needs to run.
Clogged Fuel Injectors
If the car cranks when you turn the key, but the engine won’t start, it could be because fuel isn’t getting to the engine.
One potential reason for this could be dirty fuel injectors. Over time, the fuel injector nozzles can become clogged with rust, corrosion or debris. Once clogged, the fuel injectors may not add the correct amount of fuel to the cylinders, and the vehicle may not start up at all.
To keep your fuel injectors clean and working as intended, be sure to only add high-quality gasoline to the tank. Gasoline from less-than-reputable sources that has been improperly stored or transported is more likely to contain damaging debris that could make its way through the fuel lines and to the injectors — ruining them.
Bad Fuel Pump
Another reason fuel might not be getting to the engine is a bad fuel pump. Most gasoline from chain service stations is perfectly clean and properly stored, so bad fuel injectors aren’t often the problem. You’re even more likely to suffer from a bad fuel pump.
If the fuel pump in your car goes bad, gas won’t be able to flow from the tank to the engine, and it simply won’t be able to run on its own. We’ll simply recommend that you have the pump replaced.
Bad Spark Plugs
If the engine holds compression well, and the fuel system is working correctly, but it still won’t start, that tells us that your car’s spark plugs may not be working. The spark plugs ignite the air/fuel mixture inside the engine’s cylinders. It’s the resulting explosion that actually powers your car.
Modern spark plugs can last 100,000 miles or more before going bad and needing to be replaced, but they can go bad earlier than that for a variety of reasons: If the engine experiences too much carbon build up, this can foul your spark plugs.
Or, if oil leaks into the engine, it can coat the spark plugs and prevent them from working. The problem may also be with one of the components, like the computer or the ignition coils, that supply power to the spark plugs
Bad Crankshaft Position Sensor
Not only does the engine in your car need a spark to begin combustion, that spark has to take place at the exact right moment. Too late or too early and the air/fuel mixture won’t entirely combust, reducing performance and potentially failing to start the engine entirely.
One of the reasons your spark plugs might be firing incorrectly is due to a faulty crankshaft position sensor. It’s this sensor that tells your engine’s computer the position of all the valves and pistons at any given moment.
The ECU then uses this information to determine when to fire the spark. If this sensor has gone bad, the ECU won’t know when to fire the sparks, and the engine might not start.