Kia Optima contains light inside the trunk for illumination purposes. It is beneficial to enlighten the cargo area to arrange the luggage correctly at night and in low-light conditions. These are LED light bulbs located on the trunk’s ceilings.
Kia Optima trunk light not working can be due to a blown-out fuse, broken trunk light switch, damaged electric bulb, wiring issues, weak batteries, and broken light housing.
These lights contain an electric bulb similar to standard ones and last longer. However, these are also susceptible to wear and tear like the regular ones because of their broken parts and damaged electric connections. Some vehicles contain sensors that allow the lights to come on when you open the trunk lid.
| Causes | Solutions |
| Blown out fuse | Replace fuse from the driver side panel |
| Broken trunk light switch | Carefully arrange the luggage in cargo area |
| Damaged bulb | Add new electric bulb |
| Wiring issues | Replace damaged wires with new ones |
| Weak batteries | Check battery voltage |
| Broken light housing | Inspect them regularly |
Blown out fuse
Kia Optima trunk light is the electrical component and contains a fuse for the safety of their circuits. Fuses are the safety equipment that protects the devices from significant damage by breaking the circuits.
They blow out or break the circuit when they detect unusual changes in the flow of electric current. These usually blow out because of short circuits and voltage spikes.
Short circuits in electric wires can come when poorly insulated wires come in contact with metal objects and other wires. It disturbs the current pathway and allows the excessive electric current to move toward the respective devices.
Fuses blow out to break the current pathway and protect the devices. The issue also comes when these lights draw more current than in normal conditions.
Broken and damaged wires create resistance in the current flow, and excessive electric current moves toward the electric bulbs in the cargo area.
Many people install the new electric bulb in the cargo as an aftermarket addition, which is not compatible with the fuses that are present in the car and cause them to blow out.
Light housing also comes in exposure to water because of rainy weather and during deep car washing, which can lead to short circuits and burnt-out fuses.
You cannot illuminate the electric bulbs by pressing the button during this situation because of the disturbance of electric circuitry. You have to locate the fuse of these lights for inspection purposes.
Fuses are present in the fuse box that is located inside the driver’s side cabin. Remove the plastic cover, and you can see multiple fuses there.
In addition, you can also see stickers there, which provide enough information about the location of different fuse types and their amperage.
Check the position of the trunk light fuses labeled with a specific number and their amperage. Check these by connecting them with a multimeter.
Broken trunk light switch
You can activate the trunk light by using the button on the rear side of the cargo area. It is located on the cargo area’s floor near the latch mechanism.
You have to press this button to illuminate the cargo area so you can arrange the luggage at night. These buttons get power from the car’s batteries and supply the current to these electric bulbs for illumination.
Broken trunk light switches cannot supply power, and you cannot turn them on. You cannot activate them when switches cannot make their proper contact.
Moreover, these control switches are also at risk of accidental damage during loading and unloading. Mishandling while arranging various bags and luggage can damage these switches and the plastic coating. This causes wear and tear when you accidentally put heavy luggage or bags on them.
Excessive weight exerts pressure on these switches and damages their internal mechanism. They cannot conduct electricity and illuminate the lights because of corrosion on their contact points.
Moisture can trigger the oxidation reaction on the metal material of the contact points. Moreover, switches also become faulty because of their frequent use and age.
Many people complain that their cargo lights do not turn off when they close the trunk lid. It usually happens when lids are misaligned and not correctly adjusted.
Switches cannot make the proper contact because of the poor adjustment of the lid. Operating them carefully and not exerting extra pressure while using them is necessary.
Keep the heavy bags and luggage away from them so they cannot disturb their internal components. Check the latch assembly properly for proper closing and correct lid alignment.
Damaged bulb
Trunk lights mounted on the roof of the light in your car usually contain LED electric bulbs like the standard ones. Sometimes, electric connections, fuses, and buttons are fine, but still, they are not illuminating.
I also faced the same issue in my Kia Optima last month, and I checked the fuse and battery of my car, but these are working fine. I checked the power supply of the electric bulb, and it was burnt out.
You cannot illuminate these lights because of burnt-out electric bulbs. Electric bulbs in them can deteriorate over time because of their age.
These have a specific life span, and you have to replace them after their average life span. The issue also comes because of the damaged filament.
These electric bulbs contain tiny filaments for illumination purposes. In addition, filaments can also break because of overheating and long-term exposure to high temperatures.
Excessive vibrations when driving on bumpy roads increase the risk of wear and tear of these filaments. You can also face the issue when you turn the light off and on frequently.
The filament can break because of sudden temperature changes. Pry off the light housing and check the power supply in bulbs by using a voltmeter. Furthermore, the burned bulb also appears dark brown because of its damaged filament.
You can remove the old electric bulb and install the new one compatible with the fuse’s amperage near the driver panel. We prefer to install high-quality electric bulbs so they can last longer.
Wiring issues
Electric wires are connected to these trunk lights to supply power for their illumination. These wires help connect the buttons to the lights.
You cannot illuminate the Kia Optima cargo area after pressing the button because of the damaged wires and electric connections. Damage wires cannot supply enough power to these components.
In addition, the issue also comes because of short circuits and damaged insulation layers. Short-circuited wires cause resistance in the flow of electric current.
Moreover, the electric wire connections also become loose because of their age and driving on bumpy roads. You have to replace the faulty wires with new ones for a smooth current supply.
Weak batteries
Batteries supply the power for the illumination of trunk light. You cannot turn them on because of insufficient power supply from the electric source.
My friend experienced a faulty trunk light issue last week. He told me the lights suddenly turned off and checked the fuse, but it was fine.
He took his Kia Optima to the dealerships for inspection of their parts. Experts told him that the issue came because of the weak batteries of the vehicle.
Batteries can last for 5 to 6 years when these are adequately maintained. Check the battery voltage by connecting them with a multimeter and replace the dead or weak ones.
Broken light housing
The light housing is the external cover or shell that covers the light and its internal components from the exterior environment. These trunk lights also stop functioning because of the damaged light housing.
These outer cases are made of glass material, and the chances of their wear and tear increase when something hits them during loading and unloading.
In addition, cracks can also appear on them with time. Cracks can also come on glass material because of exposure to high temperatures.
Moreover, water can penetrate through the cracks and small openings, damaging the electric bulb and its internal components.
You should check the light housing regularly to inspect the cracks and damages on their surface. Always try to park your Kia Optima in shady areas during summer to decrease the risk of environmental-related damage.
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