Relay with information about the need for replacement

The relay in a car is an electromechanical device that allows you to close or open an electrical circuit with high currents.

It helps the driver, as well as through control units and in automatic mode, to turn on and off electrical devices in the car. For example, when the driver presses a button on the dashboard or uses a steering wheel switch, various functions in the car like windshield wipers, air conditioning, headlights, seat or rear window heaters, cabin heating, or window lifts start operating.

In modern cars, a fairly large number of relays are used. To more quickly identify vehicle malfunctions, car manufacturers group relays into assembly blocks. Often, if something stops working, like the radiator fan, it means that either the fan itself, the wiring, the control unit, the relay, or the fuse has failed. In this case, we recommend immediately going to a trusted, certified center to a technician who specializes in automotive electrical systems for diagnostic tests. Doing so will save you both time and money, as it's not possible to identify the malfunction of a non-working fan or other electrical equipment in the car without specialized training and knowledge. Even the simplest tasks can be very difficult, like identifying the location of the assembly block and the specific relay responsible for the function of an electrical device.

During diagnostics, if the technician finds that the relay is indeed not working, a simple replacement is usually made. Relays are generally not repaired, as the contacts tend to oxidize and deform due to heating. An exception might be the starter relay; usually, the contacts in this relay just oxidize and cleaning them can restore functionality. Relay replacements should be done with the car's battery disconnected.

A malfunctioning relay can lead to an electrical circuit either disconnecting—resulting in, for example, the engine failing to start—or short-circuiting, in which case you might not be able to turn off the headlights. Our advice in such situations is to disconnect the battery to avoid full discharge and reconnect it only so that you can drive to a repair shop.

"Relay Replacement" fixes "Car Relay Failure"

Above is a list of relays that most commonly fails.

You should take your car to an auto shop any time a relay overheats and melts; the problem might be serious.

You can find more details and information about shops performing these inspections in your areahere.

The AutoTechIQ ranking for Safety, Cost Avoidance, and Environmental Impact is

env level
env level
Cost Avoidancei
env level
env level
Environmental Impacti
env level
env level
Four common causes for a plastic burning smell from the vehicle and their related parts.
This fix will help eliminating

Burning Plastic Smell

The burning plastic smell is typically related to any electrical system overload. Plastic coatings on wires can become heated beyond their limits. Burning can also occur when there is an electrical short circuit.

  • Melted fuse box: The fuse box holds many fuses and connectors and has a vital role in the car's electrical system by protecting circuits and components. However, it can burn if there's an electrical overload or short circuit, producing a burning plastic smell.
  • Faulty blower motor: The blower motor is a mechanism that forces airflow in the vehicle and is essential for A/C and engine cooling. However, it can overheat due to internal electrical issues, causing a burning plastic smell.
  • Faulty alternator: The alternator is crucial to the electric system in a car; it's basically the powerhouse that generates and recharges the battery. Unfortunately, it can overheat and burn internal components, causing a burning plastic smell.
  • Road plastic on the exhaust: Road plastic like shopping bags or plastic debris can bounce on the exhaust and get stuck from the heat. In this case, the plastic keeps burning and producing a telling smell.
  • Relay failure: Relays are vital components in the electrical system; they transfer electricity from the control circuit to the main circuit, basically making a small switch activate a bigger car function(like turning a switch to activate the headlight). However, they can overheat due to exaggerated power drawing, causing a burning plastic smell.

A burning smell coming from the car is typically an early sign of damage. Unfortunately, turning a blind eye to the problem puts expensive wiring, harnesses, connectors, and computer controls at risk.

First, search under your vehicle for plastic bags stuck in the exhaust. In some cases, the plastic melts, and the burning smell travels through the heater and air-conditioning vents. If the problem persists, serious car problems might evolve.

Since most modern cars and trucks have a substantial amount of computer, electrical, or sensor wiring to ensure all essential control functions in your vehicle are working, it is vital to keep them running correctly. Be prepared to share with your trusted shop how they can best reproduce what you’re experiencing during their testing.

Learn More about the Symptom
Is Relay Replacement
Your Issue?