When any lights on your Toyota Corolla develop problems, whether it's the headlights, dome lights, dashboard lights or any other lighting, it can be unsettling and sometimes dangerous if you are driving at night. The source of the issue may require a simple fix or be a symptom of a larger problem. You don't need to be an automotive or electrical expert to do some basic troubleshooting of the problem. Many times you can resolve the issue yourself without having to take your car to a mechanic.
Identify the nature of the problem, such as if the lights are dim or not coming on at all. Also identify if all lights are affected or if it's only one or a few lights. This helps determine the source of the problem.2
Locate and test the lighting controls. On many Corolla models, the dashboard lights have a dimming knob. Ensure that the dimmer is turned up so that the lights are receiving power. This knob is usually located to the left of the steering wheel. Also, Corollas are sometimes equipped with a master switch for interior lighting, typically located on the center console. Ensure that the switch is set to the "On" position. For the exact locations of dimming knobs and on/off switches, refer to the owner's manual for your Corolla.3
Check the overall power to the car. If other accessories in the car, such as the radio or windshield wipers, are not functioning or are exhibiting erratic behavior, the car's battery may be low or dead. Recharge or replace the battery if necessary. The battery in a Corolla is typically located directly behind the driver's side headlight in the engine compartment.4
Examine the fuses. If one or more fuses are broken, certain lighting features will not receive power from the battery. The two primary fuse boxes in a Corolla are located under the dashboard on the driver's side to the left of the steering wheel, often behind a small door, as well as on the driver's side in the engine compartment, just behind the battery, inside a black covered box. To check the fuses, remove the cover or door and use fuse pullers to remove the fuse. If the metal connector inside the plastic is broken, the fuse must be replaced.5
Check the integrity of the light bulb. If only one or two bulbs are not functioning and the fuse is intact, the light bulb may be burned out. Some bulbs may be difficult to remove based on their accessibility. If you can remove the bulb from the light socket, you can check to see if the filament is still intact. If you replace the light, ensure you obtain an exact model replacement. Check the owner's manual for your Corolla or contact your local Toyota dealer's service department to determine the model of the bulb.6
Determine if the wiring leading to the light is conducting electricity. Connect the negative lead on the test light tool to the negative terminal on the car battery. Then connect the positive lead on the test light tool to the positive wire on the headlight wiring harness. If you are uncertain which wire is the positive wire, consult your owner's manual for the wiring diagram. If the light is receiving electricity, the light in the test light tool will glow. If the test light tool does not light up, there may be a problem in the wiring leading to the light.