Skip to Content

Left Car Lights On Overnight? Here’s What You Need To Know

Left Car Lights On Overnight? Here’s What You Need To Know

In most cases, it’s a one-time mistake of leaving the car lights on overnight. While in others, you may repeat the mistake one or more times.

In either case, it’s common for anyone to forget to turn off the car lights. But is this necessary to turn off the lights when not in use?

How will leaving the car’s lights on the overnight affect the car? Will doing so affect the car in other ways? If you are seeking answers to these questions, get them here in the below sections.

Can you leave the car lights on overnight?

No, you cannot leave your car lights on overnight. Doing so will drain out your car’s battery, and the following day when you’ll try to start your car, it won’t start.

It is because the battery is responsible for powering all your car’s accessories (modifications also) as well as the cranking system or starter.

The starter is responsible for turning your engine on after you rotate the car keys after inserting them.

Hence, if the battery becomes dead due to power consumption overnight, the car won’t start. Also, leaving your car lights on overnight may make you replace your current battery with a new one.

What happens when you leave your car lights on overnight?

So, now that you know about the prominence of a car battery and its functions, you may wonder what else can happen when you leave your car lights on overnight.

So, here are some possibilities to happen if the battery becomes dead due to leaving the lights on overnight.

Dim lights or lights won’t turn on

When you leave your car lights on overnight, it will slowly drain out the battery. As a result, the next day, lights will appear dim or flicker continuously if the battery isn’t completely dead.

If it’s completely dead, the lights won’t start. Also, the dome lights will remain dim or won’t turn on if you’ll open the door.

No radio

If the battery gets less power or is dead due to lights left on overnight, you will notice that the radio won’t work. Also, you will hear no regular chimes as soon you’ll insert the keys to turn on the ignition.

Non-functioning accessories

If the battery is a half charge or utterly dead, the various car accessories won’t turn up if you left the car lights on overnight.

These accessories include the digital gauge, any LCD screen, and every other car accessory the car houses.

No crank or weak crank

If the battery is dead or has insufficient power, you will hear no crank after starting the ignition, or it’ll crank weakly. In some cases, the battery and alternator can have issues and result in less or no cranking.

The car starts and dies immediately

It is a strange observation and common in particular models. While the battery may have enough voltage to turn on the engine, the car may stop suddenly and won’t start again.

Yes, there may seem more than the battery issue behind this; checking the battery first should be the first resort.

The car starts suddenly and slower

If the battery isn’t complete, the car may take more time to start or start suddenly like never before.

While the car’s slow starting may appear normal at times, it ought to suck more power from the battery, and this will lead to your battery’s quicker discharge.


Your car’s battery holds particular interest concerning your car’s functionality and operation. Leaving the car’s lights on overnight can give rise to several issues.

One major of them is the draining of your car’s battery. Yes, a car’s battery comes with a unique mechanism to operate for several hours.

However, in some cases, it can drain out quickly, and that’s due to the overconsumption of the battery. In turn, it gives rise to other issues that you can read about in the above sections.