Located on the sides of the car, the turn signals notify others of the car's future maneuvers. Knowing how the turn signal relay works will help solve problems that arise with this device.
Principle of operation of turn signal relays
Turn signals are one of the mechanisms of the lighting system. This paired device is located on both sides of the car:
- As sections in the front and rear lights
- As separate bulbs on the front fenders
- Integrated into the external rearview mirrors
Unlike other lighting devices, turn signals flash intermittently and light up synchronously all around. They are activated by the movement of the lever under the steering wheel. The hazard lights activate the external indicator bulbs throughout the car.
The turn signal relay is an electronic device that organizes the entire process. The operation of the turn signals, regardless of the type of bulbs (LED, halogen, or incandescent), largely depends on this device. It is responsible for several functions:
- Creates an intermittent signal in the bulbs
- Displays a flashing light in the form of a green horizontal arrow on the dashboard
- Emits characteristic clicks (or other sounds) that let the driver know that the turn signals are on
- Activates all bulbs when the hazard lights are on
The principle of operation of turn signal relays is based on interrupting the electrical circuit. The charge from the battery constantly flows to the bulbs, so without the electrical device, they would simply stay lit. The flashing is achieved by periodically interrupting the flow of electricity. The turn signal relay device was originally an electromagnetic-thermal one, later replaced by an electronic one.
The electromagnetic-thermal sensor is an extremely simple and reliable technical solution. Today, such a device can be found in cars manufactured in the 1980s. The design consists of a metal housing, inside of which there is a core with a copper winding. On the sides of it are contact groups and armatures, one of which leads to a nichrome wire. The electrical circuit of the turn signal interrupter relay consists of a sequence of "wire - resistor - winding - light source". When the current passes through the wire, it heats up and stretches, moving the armature to the side. At this moment, the maximum allowable amperage flows to the bulb bypassing the resistor, and it shines brightly. As the wire cools, it contracts and interrupts the circuit - the turn signal dims, even almost goes out. The characteristic sound in the form of dull clicks is emitted by a small armature when it closes and opens the circuit.
Modern turn signal relay devices
The main element of the electromagnetic unit is a nichrome wire. Its physical characteristics change the current flowing to the indicator. In an electronic device, this function is performed by a so-called key. Essentially, it is a microcircuit with transistors, a control circuit, and a clock generator. When voltage is applied, this generator emits pulses to the contact device. As a result, the charge either goes to the winding or does not. This all happens at a frequency of 60 to 120 pulses per minute.
In electronic turn signal relays, the operating scheme is almost eternal. It is not affected by external factors, temperature fluctuations, or wear and tear. This cannot be said for outdated technology. Based on the stretching of a nichrome fiber, the mechanism inherently depends on environmental conditions. After a long period of inactivity, high humidity, or low temperatures, the unit may stop functioning. Over time, the wire loses its properties and does not perform its task.
Therefore, malfunctions of old-style turn signal relays occur, affecting the driver's ability to safely operate the vehicle. But problems can also occur with new technologies.
Possible breakdowns
There are several signs that the device has stopped performing its tasks:
- The flashing frequency has changed towards an increase or decrease - this may be caused by the installation of non-standard light sources that require higher or lower current parameters. If the standard LEDs suddenly start behaving this way, the problem lies in the electrical circuit and the relay in particular.
- The turn signals have completely stopped lighting up - there are two reasons for this phenomenon: the bulbs have burned out or there is a break in the power supply
- The bulbs are constantly lit both in the on position and when the hazard button is pressed - this is a clear sign of a malfunction in the turn signal relay
The operation of such a vehicle is strictly prohibited by the Rules of the Road. If this happens while driving, the driver must inform others of planned maneuvers by using their left hand out of the window. Although the malfunction of the electrical device does not affect the vehicle's driving characteristics, the malfunction must be fixed.
Repair
To eliminate malfunctions of the turn signal, it is necessary not only to know how the turn signal relay works but also where it is located. For convenience, automakers place the unit on the fuse panel under the dashboard on the driver's side. The cover of the block usually shows a schematic layout of all the elements. Once you find the relay, you need to figure out how to remove it. Usually, it is held in place by contacts and can be removed from the socket with a little effort.
Repairing the device today is not an absolute necessity. Firstly, restoring the interrupter will require knowledge in the field of electrical engineering, and secondly, special tools and intricate modifications of the factory product will be needed. A simpler option is to simply buy a new device, especially since it is inexpensive and easy to find.
There are three ways to choose a turn signal relay:
- By VIN code
- According to the make, model, and year of manufacture
- By the markings on the relay
You can find the necessary product in Ukraine at any car market or at a scrapyard. Before heading out, the first thing to do is to check the functionality of the product by turning on the hazard lights or turning the lever. If everything lights up as it should, you can confidently hit the road.
