How to Connect a Five-Pin Relay?
2 Answers
Five-pin relays have two coil pins, one common terminal for contacts, one normally open contact, and one normally closed contact. The coil is connected to the control voltage; when energized, the relay activates, causing the normally open contact to close and the normally closed contact to open. Below is relevant information about five-pin relays: 1. The coil has a certain resistance. The normally closed contact remains connected to the common terminal when not energized, while the normally open contact remains disconnected. Whether used individually or in combination, the five pins can be divided into A, B, 1, 2, and 3, where A and B are connected to the positive and negative terminals of the control power supply, and 1, 2, and 3 are the controlled terminals. When A and B are not energized, 1 and 2 are connected; when A and B are energized, 1 and 2 separate, and then 1 and 3 connect. 2. Automotive relays consist of a magnetic circuit system, contact system, and reset mechanism. The magnetic circuit system includes components such as the iron core, yoke, armature, and coil. The contact system consists of static reeds, moving reeds, and contact bases. The reset mechanism is composed of reset reeds or tension springs. 3. When a certain voltage or current is applied to both ends of the relay coil, the magnetic flux generated by the coil passes through the magnetic circuit formed by the iron core, yoke, armature, and working air gap. Under the influence of the magnetic field, the armature is attracted to the pole face of the iron core, thereby pushing the normally closed contact to open and the normally open contact to close. When the voltage or current at both ends of the coil falls below a certain threshold, and the mechanical resistance exceeds the electromagnetic force, the armature returns to its initial state, causing the normally open contact to open and the normally closed contact to close.
Alright, let me explain how to wire a five-pin relay. There are five pins on the relay, and first, we need to identify their functions: Generally, pins 85 and 86 are the control coil terminals, connected to the switch power supply used to trigger the relay; the middle pin 30 is the common terminal, which should be connected to the positive terminal of the vehicle's power supply; pin 87 is the normally open terminal, connected to the device you want to control, such as the headlights; pin 87a is the normally closed terminal, which is rarely used and can be left unconnected. When wiring, be sure to operate with the power off—connect pin 85 to the positive terminal of the switch, pin 86 to ground, pin 30 to the positive terminal of the battery, and pin 87 to your load. Don’t mix up the positions; reversing the connections can easily damage the equipment. Remember to check if all contact points are secure, and when testing after wiring, it’s best to have someone help observe whether the load response is normal.
