What are the functions and roles of the rear taillights of a car
The main functions and roles of car taillights include:
Warn the vehicles coming from behind
The rear taillights warn the vehicles behind to pay attention to their driving direction, position and status (such as braking, turning, etc.) through red light, reducing the risk of rear-end collisions.
Improve night visibility
In low-light conditions or bad weather (such as fog, rain, snow, etc.), taillights can enhance vehicle recognition, helping other road users spot the vehicle more easily and improving driving safety.
Indicate driving status
Youdaoplaceholder0 Brake warning : When braking, the taillights and brake lights light up simultaneously to alert the vehicles behind to slow down.
Youdaoplaceholder0 Turn warning : For some models, the turn signal function indicates the vehicle's intention to change lanes through dynamic changes in the taillights.
Reversing lighting
When reversing, the taillights automatically turn on, illuminating the road behind and assisting the driver in observing the surrounding environment.
Enhance recognition
The taillight designs of different vehicle models feature brand characteristics, enhancing vehicle recognition at night and facilitating quick identification by other drivers.
Some high-end models also feature dynamic light effects (such as welcome/farewell functions and personalized light animations) and LED light source technology, further optimizing visual effects and energy consumption performance.
The fact that the rear taillights of a car remain on all the time may be caused by the following reasons:
Common causes
Youdaoplaceholder0 light switch accidentally touched
If the light combination switch on the lower left side of the driver's seat is accidentally touched to the "side marker light" position, the taillights will remain constantly lit. For some models, the "Home Lighting" function on the central control screen needs to be turned off first.
Youdaoplaceholder0 the door/trunk is not fully closed
The 2025 BYD Seal and other models are equipped with a "Light warning system", which will trigger the taillights to stay on for a long time if any door is not locked. The failure of the microswitch due to the aging of the trunk rubber strip is a common cause.
Youdaoplaceholder0 The bulb is short-circuited or damaged
Halogen bulbs that have been in use for more than three years have a short circuit risk as high as 62%, which is manifested as black fogging on the inner wall of the glass.
Youdaoplaceholder0 line fault
A short circuit or poor contact in the taillight circuit can lead to continuous power consumption. It is necessary to check whether the circuit is damaged or grounded.
Youdaoplaceholder0 sensor failure
The door sensor and the light sensor mistakenly triggered the taillights to remain constantly on. The sensors need to be inspected or replaced.
Youdaoplaceholder0 brake system abnormality
Short circuit of the brake switch, failure to release the handbrake, insufficient brake fluid, etc. can cause the taillights to remain constantly on. It is necessary to check the condition of the braking system.
Emergency handling suggestions
Youdaoplaceholder0 power-off operation : Disconnecting the negative terminal of the battery for 15 minutes can temporarily solve the problem, but immediate maintenance is required the next day.
Youdaoplaceholder0 self-check steps :
Check whether the light control switch is in the "AUTO" or "Off" position;
Make sure all four doors and two covers are completely closed.
Observe whether the status of the taillights changes with the opening and closing of the car doors.
Check the liquid level and switch status of the braking system.
If self-inspection fails, it is recommended to contact professional maintenance personnel to test the circuit and control module.
The treatment methods for water ingress and fogging in the rear taillights of a car need to take different measures based on the degree of water ingress. Youdaoplaceholder0 slight fog can be dealt with through natural evaporation, while severe water ingress requires professional inspection .
Youdaoplaceholder0 handling methods depending on the situation
Youdaoplaceholder0 light fog (no standing water) .
Turn on the taillights for about 30 minutes to use the heat from the bulbs to disperse the moisture.
Remove the dust cover to accelerate air circulation and combine it with natural drying or low-temperature drying with a hair dryer.
Blow air with a dry air gun (make sure the air gun has undergone water removal treatment).
Youdaoplaceholder0 more water droplets (no dripping water formed) .
After removing the taillight assembly, turn it upside down to dry and focus on checking the integrity of the sealing rubber strip.
Use dehumidifiers in a well-ventilated environment to assist in drying.
Youdaoplaceholder0 severe water ingress (dripping water) .
Immediately stop using the vehicle's electrical system to prevent short circuits.
Go to a 4S store or a professional repair point for:
Lampshade sealing performance test.
Vent pipe unblocking.
Replacement of damaged parts (such as lampshades, sealing rings, etc.).
Youdaoplaceholder0 daily maintenance suggestions
When washing the car, avoid direct exposure of the high-pressure water gun to the gaps between the taillights.
Check the aging condition of the taillight sealing rubber strips every quarter.
After parking in the rain, open the trunk in time for ventilation and dehumidification.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
