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What Are Common Types of Automotive Relays?

Automotive relays are electromechanical relays found in automobiles such as cars, trucks, cans, and trailers, and they may be used for numerous applications to control circuits. As a wide variety of options exist to tackle different needs, it can be very important for one working with such components to have a basic understanding of each and what they do. In this piece, we will provide a brief overview of the most common types of automotive relays, their design, and applications.

Change Over Relays

The change over relay is the most common relay type found in automobiles, and they feature a 5 pin configuration that can either be Normally Open (NO) if pins 30 and 87 are used or Normally Closed (NC) if pins 30 and 87a are used. To establish the Change Over setting which combines NO and NC operations, pin 30, 87, and 971 are used. When in this mode, the relay will switch current between circuits based on whether the coil is on or off.

Normally Open (NO) Relays

Normally open relays are those that can only be wired in a single way, that of which is normally open. This is because they only contain four pins for configuration, unlike the five pin standard seen in change over relays.

Flasher Relays

Flasher relays featured even fewer pins than some of their counterparts, featuring two or three pins in total. If a flasher relay only has two pins, then a connection would be established to the power supply and the light circuit. With a three pin configuration, the third pin would be attached to the indicator light that allows the operator to know that the flasher is activated. In some instances, a flasher relay may act closer to a circuit breaker than a conventional relay based on how they are designed and grouped.

There are a variety of flasher relay subtypes that one may take advantage of based on their needs, those of which include the thermal flasher, electromechanical flasher, LED flasher, and Wig-Wag flasher. Thermal flashers are those that are comparable to a circuit breaker, operating through thermal control. As thermal flashers can easily and quickly make and break connections, they can be used for the operation of turn signals and similar equipment.

Time Delay Relays

Time delay relay components feature the ability of being adjustable, and they can ensure a constant flow of current through contacts. Depending on the need for current, the direction of flow can be set as required, ranging from a flow lasting second to one lasting minutes. Once the time duration is met, the coil will switch off. In order to manage timing and current flow direction, a time delay relay utilizes a solid-state timing circuit with a variable resistor. Generally, these relays are used for powering parking lights after the vehicle is shut off, or other similar applications.


Once you have determined the types of automotive relays that you need to successfully carry out operations, utilize Aviation Sphere to save time and money. Aviation Sphere is a premier purchasing platform belonging to the ASAP Semiconductor family of websites, and we are unmatched in our ability to fulfill customer needs with quality service and top-notch parts. Explore our vast offerings as you see fit, and our industry experts are always on standby and would be happy to assist you with customized quotes for your comparisons and personalized assistance. With our unwavering efforts to consistently improve quality control practices and export compliance, we proudly operate with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation. Give us a call or email today and see how Aviation Sphere can serve as your strategic sourcing partner for all your operational needs. 


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