Introduction
Relays are often used in vehicles in which the headlight systems are controlled by a computer to manage both the low and the high beams.
The headlight relays are prone to failure over time, similar to any other form of a relay. That will cause the headlights bulbs to stop working properly. You need to take care of this problem immediately.
The design and functioning of the headlights bulbs in your car depend greatly on the relays. Therefore, if your relays are faulty, it could be quite serious.
Thankfully, the relays offer you several warning signs and indications before they completely shut down. The key is to remain alert and take preventive action if necessary.
Working Of Headlight Relay
A relay is simply a reduced electromagnet that controls a relatively high circuit. A wire and a switching device with a pair of connections are both on the inside of a relay. Until the relay is activated, most car relays are generally open, which means that power does not go between the contacts.
A normal headlight circuit that is controlled by the computer has relays that are generally known as two relays. In this case, one relay is for the full beam and the other one is for the lower beam. A third headlight relay to turn on the daytime driving lights is also included in some vehicles
It’s important to note that not all headlight systems controlled by computers require relays. For instance, in some systems, the BCM – Body Control Module transmits a request for headlight operation to a specific kind of intelligent plug socket, also known as an integrated energy module. The also has integrated drivers to turn on the low beams after receiving the request from the Body Control Module.
Additionally, headlight relays are typically absent from earlier, computer-less headlight systems. The dimming switch usually allows current to pass straight from the headlight button to the headlights.
Common Bad Headlight Relay Symptoms
#1 The headlight will not turn on
Lack of function in the headlights is the most typical sign of a damaged headlight relay. Usually, a headlight relay will fail in the open spot, cutting off power to the headlights bulbs
The low beams won’t function if the low beam relay breaks. In the same way, if the relay for the high beams or the daytime running lights fails, neither the high beams nor the daytime lights will work.
#2 Headlights will not turn off
Even though it happens rarely, a defective headlight relay sometimes can stay closed, stopping the headlights bulbs from going off.
Circuits that constantly transfer power to the headlight relay are prone to issues.
#3 Covered headlights will not work effectively
Some cars, especially sports cars, feature hidden headlights bulbs that flash when turned on. The hidden headlights are computer-controlled lights that a relay activates on new cars.
The hidden headlights bulbs will not turn on if that relay breaks when it is opened.
#4 Headlight doors open or close abruptly and perform strangely.
Another sign of a potential faulty or failed headlight closing relay is irregular headlight door action. The headlight bulbs could act strangely and break as a result of a bad relay.
The headlights bulbs may quickly, randomly, or rapidly open and close, blocking their ability to provide sufficient visibility.
Similar symptoms may also be caused by a faulty engine or cabling, so it is strongly advised to get the car carefully checked.
Even though headlight bulb closing relays are not typically seen in current cars and new models, they can still break down and need to be repaired in a few older models. Have the car checked out by a qualified mechanic if you think the headlight closing relay may be damaged.
FAQ
Q. What is the procedure to test the Headlight relay?
Relays for cars are often pretty similar. A headlight relay can be tested most easily by temporarily replacing it with an additional (unimportant) relay from the electric supply box.
For instance, if the designs of the two relays are similar, you may switch the headlight relay with the air conditioning unit compressor relay. If the replacement relay is put in and the headlights function, the headlight relay must be changed.
Q. Where is the Headlight relay located?
You can find the Headlight relay in the electrical distribution unit of the engine block. In case you need support locating the relay, refer to your owner’s manual.
Q. What is the cost to change the Headlight relay?
You can generally do the replacement of a headlight relay all by yourself because it is a simple process. If you still want to go ahead and change then the costs are approx $30. The actual price will vary based on several criteria, including the brand, model number, and year the car was made.
Conclusion
It is strongly recommended by many users to get the headlights bulbs changed from the reputable store SuncentAuto. Since they have their manufacturing facility, you will get good discounts online. They also provide free shipping.
There is a guaranteed return policy of 90 days. Their customer service is available round the clock. On their website, they also have an advanced filter so that you can find the compatible product based on the year and make of the car.
