How to Connect a Car Horn Relay?

3 Answers
MacEzra
07/23/25 8:29pm
Disconnect the non-ground wire from the horn and connect it to the terminal labeled 'button' on the relay, leaving the horn ground wire untouched. Then, connect the terminal labeled 'battery' on the relay to the positive terminal of the battery using one wire, and use another wire to connect the other terminal on the horn. Finally, ground the relay housing. Below is an introduction to the relay and electric horn: 1. Relay: A relay is an electrical control device, commonly used in automated control circuits, where it serves functions such as automatic regulation, safety protection, and circuit switching. 2. Electric Horn: A car electric horn produces sound through the vibration of a metal diaphragm. It consists of components such as an iron core, magnetic coil, contacts, armature, and diaphragm.
Was this review help?
8
0
Share
AubreeMarie
08/10/25 4:03pm
I once helped a friend repair a car in the garage. Installing a horn relay mainly makes the horn work more smoothly and reduces the burden on the original switch. The operation is quite simple: first, disconnect the negative terminal of the battery to ensure safety. Then locate the original horn switch wire and connect it to the control terminals of the relay, usually pins 85 and 86. Connect the main power line to pin 30, and the output terminal pin 87 to the positive terminal of the horn. Finally, don’t forget to connect the ground wire to the car body or ground terminal. The whole process can be done with basic tools like pliers and electrical tape to avoid exposed wires causing a short circuit. After completion, reconnect the battery and test it—the horn should sound much louder. This method is suitable for most car models, and the key is to proceed step by step patiently without rushing to power it on. Remember to regularly check the connection points for oxidation, as prevention can save a lot of trouble.
Was this review help?
18
2
Share
Expand All
MacDonovan
09/23/25 3:33am
I've been driving for years, and connecting a horn relay is a piece of cake for me. The key is to protect the original switch: you pull out the original horn's switch wire and connect it to terminals 85 and 86 of the relay; the main power positive (taken directly from the battery or relay box) connects to terminal 30, and the output terminal 87 connects to the horn's positive. Make sure the ground wire is securely fastened. Always disconnect the battery fuse before starting—safety first. All you need are a screwdriver and some tape, nothing complicated. I've helped neighbors with this before, took about ten minutes, and the horn sound even improved. If the wiring is old, replace it sooner rather than later to avoid damaging other components later. Remember, when testing after wiring, just honk twice—keeping it on for too long isn't good for the relay. This kind of job is perfect for car owners to do themselves—saves money and teaches a skill.
Was this review help?
19
2
Share
Expand All
More Forum Discussions

How many questions are there in Subject 1, and what is the total score?

According to the "Regulations on the Application and Use of Motor Vehicle Driving Licenses," the Subject 1 test for the driving license consists of 100 questions, divided into single-choice and true/false questions, with each question worth 1 point, totaling 100 points. If 11 questions are answered incorrectly during the test, the system will automatically submit the paper and end the exam. Subject 1, also known as the Subject 1 theory test or driver theory test, is part of the motor vehicle driving license assessment. The test content includes theoretical foundations of driving, road safety laws and regulations, local regulations, and related knowledge. The test is conducted on a computer, with a time limit of 45 minutes. Subject 1 test content: Driving license and motor vehicle management regulations; Road traffic conditions and regulations; Road traffic safety violations and penalties; Road traffic accident handling regulations; Basic knowledge of motor vehicles; Local regulations; Knowledge of braking systems and safety devices for large and medium-sized passenger and freight vehicles; Specialized knowledge for wheeled self-propelled machinery, trams, and trolleybuses. Subject 1 test precautions: During the Subject 1 test, students should pay attention to their attire—no slippers are allowed, and electronic devices and bags are prohibited in the examination room. Bring your ID card and queue to enter the waiting hall. Observe the precautions and procedures on the large screen, and store personal belongings in lockers before entering the examination room. Upon entering, verify your identity at the assigned seat and begin the test. Ensure the camera is aligned with you and adhere to exam discipline. If you fail the first attempt, there is a retake opportunity on the same day. If you fail again, you must pay to reschedule. After the test, queue to collect your score report and sign it—unsigned reports are considered invalid. There is no limit to the number of times you can reschedule the Subject 1 test. Each subject can be taken once, and if you fail, you can retake it once. If you do not attend the retake or fail it, the current test session ends, and the applicant must reschedule. In contrast, Subject 2 and Subject 3 allow only five attempts. Subject 2 and Subject 3 tests must be rescheduled at least ten days later. If you fail the Subject 3 safe and civilized driving knowledge test, the previously passed road driving skills test results remain valid. There are three subjects in the driving test: Subject 1, Subject 2, and Subject 3. Subject 1 refers to the road traffic safety laws, regulations, and related knowledge test; Subject 2 refers to the field driving skills test; Subject 3 is divided into two parts: road driving skills and safe and civilized driving knowledge tests.
17
0
Share

How to Repair Engine Block Deformation Caused by Overheating?

If the engine block is deformed, it can only be replaced. The following introduces the repair method for engine block cracks: 1. Use coarse sandpaper to remove rust around the crack on the engine block. When sanding to a certain extent, the end of the crack can be located. 2. Then, directly perform welding with a patch plate. However, be cautious of warping at the welded area. If warping occurs, immediately hammer the welded area while it's still hot to prevent residual slag. 3. After patching, place an asbestos gasket between the patch plate and the engine block (or cylinder head), and apply a layer of lubricating oil on both sides.
13
2
Share

What does the check light mean?

check light is the engine fault light, which indicates that there is a problem with the engine when it illuminates. Here are some introductions about car fault lights: 1. There are many indicator lights on a car, such as the engine self-check indicator, oil pressure indicator, handbrake indicator, and coolant temperature indicator, each representing different meanings. Generally, when a red light comes on, you should be extra vigilant, contact professionals for solutions, and avoid continuing to drive. 2. If a problem occurs, promptly go to a 4S shop for vehicle inspection and repair to avoid risks and ensure personal safety on the road.
19
3
Share

Can You Die from Sleeping in a Car with the Windows Closed?

Sleeping in a car with the windows closed can indeed be fatal. Here are the reasons: 1. In a sealed vehicle, the oxygen supply is limited. As a person sleeps, they continuously consume oxygen without fresh air replenishment, leading to hypoxia, suffocation, and potentially death. Additionally, most car interiors are made of PVC (polyvinyl chloride) derived from petroleum, and the adhesives used contain formaldehyde. In an enclosed space, occupants are prone to dizziness. 2. If the air conditioning is running, the car produces significant amounts of carbon monoxide. The concentration of carbon monoxide increases over time, exceeding safe levels within approximately 20 minutes, causing noticeable suffocation symptoms.
4
1
Share

How to Repair a Blocked Expansion Valve?

Here are the methods to repair a blocked expansion valve: 1. For dirt blockage, if it is not very severe, replacing a dry filter is sufficient; if it is very severe, it is necessary to clean the impurities in the system pipeline again, vacuum, and recharge the refrigerant. 2. For slight ice blockage, you can apply a hot towel to the ice blockage area; if the ice blockage is more severe and has affected the normal operation of the system, it is necessary to clean the moisture in the system pipeline again, vacuum, and recharge the refrigerant. 3. Expansion: The main cause of dirt blockage is the presence of impurities in the system, such as welding slag, copper chips, iron chips, fibers, etc. The cause of ice blockage is excessive moisture in the system.
18
5
Share

How much horsepower does the Toyota Prado 2700 have?

Toyota Prado 2700 has a maximum power output of 120kW (163 horsepower) at 5200 rpm. Relevant information about the Toyota 2700 is as follows: 1. The Toyota Prado 2700 is equipped with a newly developed Toyota 2TR-FE engine, a four-cylinder electronic fuel injection system with a displacement of 2694cc. It offers excellent power performance and meets the latest Euro III emission standards, making it highly environmentally friendly. 2. The advanced engine of the Toyota Prado 2700 provides strong output power and torque, paired with a highly robust frame and reinforced suspension system, resulting in impressive off-road capability and passability.
16
2
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.