Catalog
Introduction
Manufactured in Europe to exacting original equipment standards under ISO9001 supervision. The 5 pin relays have silver contacts for long-lasting performance and a removable metal mounting tab for easy installation. All relays have a 500,000 cycle rating and a braided power strap for increased reliability. Available in a variety of amp ratings in 12 or 24-volt configurations, with the option of resistor or diode style circuit protection.
5 pin relay
Ⅰ What are 5 Pin Relays Used for?
A relay with five pins typically has two to operate the coil and three to incorporate an SPDT switch function with a common and a normally open contact (open when the relay is unenergized and connected to common when the relay is energized) and a normally closed contact with the opposite function. This is sometimes referred to as a Form C contact.
Complex switching, SPST NO, SPST NC, SPDT, 2PDT, and 4PDT are all common types of relays. The last would necessitate the use of 14 pins.
So, what exactly are SPDT relays used for?
The standard relay has four pins and is an SPST NO relay that closes when actuated. When actuated, an SPDT relay can perform the function of an SPST NC relay. This could be used to have a disabling circuit interrupt some operation.
1.1 Why Do You Need a Relay?
Relays in the automotive industry allow you to use a small switch inside the car to control the flow of electricity through a larger amperage circuit located any distance away from the switch. The majority of switches used in the automotive industry are only rated for a small amount of amperage. Many circuits in a car are rated at higher amperages than the switches, which means that if the circuit were wired directly through a switch, the switch would melt, break, and possibly burn. When a relay is used, however, the circuit becomes much safer and more reliable. Most relays have much higher ratings than switches. So you could use a 5 amp switch to control the 30 amp relay from a distance. The relay is turned on and off by the 5 amp switch. The high amperage circuit is controlled by the 30 amp relay.
This is an electromagnetic relay.
Electromagnetic relays are also classified based on their operating principle, such as armature attraction type, induction type, and so on. The relay depicted above is an electromagnetic attraction type. The armature is attracted to the pole of an electromagnet in this type of relay (coil).
Ⅱ How to Wire a 5 Pin Relay?
An SPDT (Single Pole Double Throw) switch is used by the Bosch 5 pin relay,
Pins 85 and 86 are linked to the 12v coil, which powers the SPDT switch. Pins 30 and 87a are connected when the 12v coil is not powered. Pins 30 and 87 are connected when 12v is applied to the coil (pins 85 and 86).
Pin 30 is typically connected to the positive (+) 12v source (battery (+) post or ignition switched power) via a fuse. The LOAD (horns, lights, siren, etc.) is wired between pin 87 and the negative (-) power source (Battery (-) post or vehicle ground/chassis/engine block, etc.). Connect pin 86 to the same positive 12v source as before, and pin 85 to one post of any push-type switch, with the other post connected to vehicle ground. That is an example of a relay-controlled horn circuit.
Your horn can be used in place of the lights in this example (s).
In automotive design, the switch is typically placed on the "ground" side of the relay, rather than the +12v side.
Standard 5 pin (SPDT) relays have two pins (85 and 86) to control the coil and three pins (30, 87, and 87A) to switch current flow between two contacts. They have connection pins that are both normally open and normally closed. When the coil is turned on, the current is switched from the normally closed pin (87A) to the normally open pin (87B) (87). Example:
2.1 5 Pin Relay Diagram
5 pin relay wiring diagram
This is useful for a variety of applications, including:
- Setting up a camera to detect reverse light.
- Many aftermarket amplifiers have a remote output.
- Additional power for devices that require more current.
2.2 How to Wire a 5 Pin Relay with a Positive Trigger?
Pin 30 - Through a fuse, power is routed from the battery to this pin.
Pin 87 - Power comes out of this and goes to any accessory when your switch is turned ON.
Pin 86 - The switch provides power to this pin.
Pin 85 connects to the ground.
Pin 87A - When the switch is turned off, power is drawn from this pin. It is not required to be used and can be completely ignored if not required.
2.3 How to Wire a 5 Pin Relay with a Negative Trigger?
Pin 30 - Power goes from the battery and into this pin, through a fuse.
Pin 87 - When you turn on your switch, power comes out of Pin 87 and goes to any accessory.
Pin 86 - Power goes into this, jumped over with a wire from pin 30.
Pin 85 - This goes to one side of your switch.
Pin 87A - Power comes out of this when the switch is OFF. It do not need to be used, and can be ignored entirely if it is not needed.
Switch - One side of the switch gets the ground wire from pin 85, the other side of the switch goes to ground. Unfortunately, with this design, you cannot easily have a light-up switch.
Ⅲ Are all 5 Pin Relays the Same?
The only thing they have in common, without a doubt, is that they both have 5 pins.
Everything else is for sale...
Though it is possible, not guaranteed, that two of these are the coil and the other three are the common, normally-closed, and normally-open contacts of a single-pole double-throw switch.
What will most likely be different is just about everything else: the voltage at which the coil is designed to operate. The rating of the contacts, as well as the number of volts and amperes. Pin-out, indicating which pins have which internal connections. Nothing of this is standard.
If you look at the datasheet, you'll notice that the important ratings are often printed on the case of the relay itself.
Ⅳ How to Test a 5-pin Relay Using a Digital Multimeter
Most electrical components in a car or other machine are now controlled by a 5 pin relay. If a component fails, there is a chance that a relay in your connections is faulty. There are only a few investigations that must be carried out before determining whether the relay is defective or not.
4.1 Testing the Relay’s Coil
To obtain the coil's resistance, consult the datasheet, which also contains the coil's tolerance value. Take note that if the resistance value is 320 and the tolerance value is 10%, the resistance value should be between 288 and 352.
Connect both lead probes to your multimeter and set it to ohmmeter settings. You don't have to be concerned about which probe should be connected to which port. It's because what we're after is resistance, and polarity has no effect on resistance. Take a look at the display screen to see how much resistance there is. If the readings are within the range specified on the datasheet, it only confirms that the coil is in good working order. If the readings are not within the range, i.e., very high or very low, the coil is malfunctioning. Because the coil is not repairable, you are only left with the option of replacing it.
4.2 Testing the Relay’s Terminal
Now that we've examined the coil and discovered the results, it's time to check the 5 pin relay's various terminals. The best way is to measure the resistance between the terminals. I will assist you in testing the following;
- Normally open terminal
- Normally closed terminal
- Common terminal
4.3 Testing Normally Open Terminal
Here's a guide to help you through the process of testing the normally open terminal.
- Set the multimeter to read resistance, i.e., in the ohmmeter mode.
- Connect one of the multimeter probes to the COM terminal and the other to the normally open terminals. You don't need to be concerned about polarity because we're measuring resistance.
- Take note of the readings on the multimeter's display.
The resistance should be measured in milliohms. This indicates that the normally open terminal is not faulty and is functioning properly. When you get a high value of resistance, i.e., much higher than a few milliohms, it means that the normally open terminals are working. Because the two are not connected, the opposition between COM and the open terminal should be high. As a result, if the reading on the screen indicates continuity, i.e., zero resistance, the terminals are faulty.
4.4 Testing the Normally Closed Terminals
If no voltage is passing through the normally closed terminal, the resistance between the COM and normally closed terminals should be zero ohms or close to it. At zero ohms, the normally closed terminal should be fine.
The following are the steps to take when performing an attest on normally closed terminals.
- Set your digital multimeter to ohms mode.
- Place one probe of the multimeter on the normally closed terminal and the other probe on the COM terminal.
- Take note of the readings on the multimeter's display.
The value should be zero. If the normally closed terminal has a high resistance between it and COM, the normally closed terminal is faulty.
4.5 Testing the Common Terminals
The common terminals are identified as 85 and 86. The resistance between the two terminals should be very low.
Here is a step-by-step guide to help you perform a 5 pin relay test on the common terminals.
- Set your digital multimeter to the ohms scale.
- Place one probe on one of the common terminals and the other probe on the other terminal.
- Take note of the readings.
If the resistance is very low or close to zero, the two terminals are functioning properly. Higher resistance indicates that the two terminals are not connected as they should be. The resistance is indicated by the multimeter because the common terminals are connected by a coil. The resistance may be influenced by the coil, but it should not be excessive.
Relays cannot be repaired. You replace them with a functional one. Because a relay switch is not a fuse, if you get stuck because the normally open terminal has a higher resistance, you can use a thin wire to close the voltage from one of the COM terminals to the normally closed terminal before you get to a place where you can replace the 5 pin relay.
Ⅴ FAQ
An SPDT relay.
2. What is the blue wire on a 5 pin trailer plug?
When you put your vehicle in reverse, the blue wire will connect to the tow vehicle's reverse light circuit, but it will also send a signal to the trailer's brake actuator to disengage it. As a result, when in reverse, the trailer brakes are not engaged.
3. Why does my trailer have 5-wires?
A 5-wire harness on a trailer connects to marker, brake, and signal lights, as well as an electric braking system. By reducing a 5-wire to a 4-wire, the connection for the trailer's brakes is removed.
4. What is the difference between a 4-pin and 5 pin trailer plug?
5 pin trailer wiring is similar to 4-pin trailer wiring, but it includes a blue wire for the reverse or backup lights. Because not all trailers have reverse lights, keep your trailer in mind when wiring in a 5-way plug.
5. Can a 5 pin relay be used in place of a 4 pin?
Yes. Bill in OKC: I changed out some relays on my bike. The originals had four pins, but the rubber holders and sockets had an extra slot for five, so they fit perfectly.