How to Test a Relay Using a Multimeter
- Test the Coil on Pins 85 & 86. To start, we’ll test the coil of the relay. ...
- Test Resistance on Pins 30 & 87. Here’s how to test a relay with a multimeter for pins 30 and 87: place the leads from the multimeter on the ...
- Add Power & Ground to Pins 85 & 86. ...
- Check for Continuity. ...
How to test a relay with a multimeter?
Here’s how to test a relay with a multimeter for pins 30 and 87: place the leads from the multimeter on the pins, and it will read the resistance. However, you shouldn’t have any resistance on any of those pins. But if you do, the switch inside is stuck closed. You should only have resistance when the coil kicks in.
How to test a relay before installing?
Before testing a relay, you must understand how it works behind the scenes. For example, if you remove the relay from the fuse box, you’ll notice that it has a weird-looking diagram along with some numbers. Those numbers or pins control different things in your relay. For example, a 4-pin relay uses pin 85, 86, 30, and 87.
What do the numbers on a relay mean?
Those numbers or pins control different things in your relay. For example, a 4-pin relay uses pin 85, 86, 30, and 87. Notice that they are spawned across the relay for the sake of convenience. Pins 85 and 86, which are parallel to each other, control the coil and two pins.
What is the voltage rating of a 12V relay?
A commonly used 12V relay will have a rating such as 10A – 125VAC, 7A – 250VAC, or 10A 30VDC. These ratings represent the maximum allowed voltages at the terminals of the relay. With that aside, here is a simple circuit typically used in cars to control the headlights.
How can you tell if a fan relay is bad?
Keep a lookout for the following bad cooling fan relay symptoms:The engine runs hot or overheats. ... The cooling fans don't work. ... The cooling fans keep running. ... Warning lights. ... Poor air conditioning performance. ... Swapping Relays. ... Measuring the Relay Coil's Resistance. ... Listening for Noises.More items...•
How do you test a fan motor relay?
7:348:41Blower Motor Fan Relay Testing and Replacement - YouTubeYouTubeStart of suggested clipEnd of suggested clipThis is exactly what you want to hear this verifies that the relay is good if your relay is good andMoreThis is exactly what you want to hear this verifies that the relay is good if your relay is good and you have no heat ventilation coming out of the vents. Then most likely it's a bad blower motor.
How many ohms should a fan relay have?
Anywhere from 50-120 ohms is OK. Out of range or open means a bad electromagnet coil winding and time for a new relay. Leave the multimeter on ohms or continuity.
How do you test a radiator fan switch with a multimeter?
2:003:55How to test your coolant fan switch - YouTubeYouTubeStart of suggested clipEnd of suggested clipI'll take my multimeter here and put it on the continuity setting. And on that setting if you touchMoreI'll take my multimeter here and put it on the continuity setting. And on that setting if you touch the leads. Together. You hear a tone. So right now there should be no tone because it's cold.
How do I test a blower fan relay?
Connect a test light or multimeter to the ground (black lead). Turn the ignition key to the on position (engine off), and remove the relay. Using the probe, test all terminal sockets in the relay connector. Two of the four should have power.
How do you check a relay?
1:196:53How to Test a Relay the Correct Way - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd then we're gonna listen for a click. There we go that's the clear. Okay so most people wouldMoreAnd then we're gonna listen for a click. There we go that's the clear. Okay so most people would stop at this and call this a good relay. But in order to be 100% sure which I strongly recommend.
How do you tell if a relay is bad with a multimeter?
Take the leads of the multimeter and connect them across the coil terminals of the relay. For a normal coil, the multimeter should read anywhere between 40Ω to 120Ω. If the coil is damaged i.e., it is open, the meter shows out of range and you have to replace the relay.
How do you test a 4 pin relay with a multimeter?
9:4514:10How to Test a 3, 4 or 5 Pin Relay - With or Without a Diagram - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd then you just touch random pins and unless you get a reading of between 50 to 120. There. We goMoreAnd then you just touch random pins and unless you get a reading of between 50 to 120. There. We go we got a 112 ohms.
How do you test a 2 pin relay with a multimeter?
2:153:11Relays - how they work and how to test with multimeter - YouTubeYouTubeStart of suggested clipEnd of suggested clipAgain put your test leads across the two thick terminals on the bottom of the relay. And then useMoreAgain put your test leads across the two thick terminals on the bottom of the relay. And then use your finger to actually physically close to the contacts.
Which relay is for radiator fan?
The fan relay is usually located near the bottom of the engine compartment on a metal frame member. The metal acts as a heat sink to keep the fan relay cool. So, unplug the connector at the relay and repeat the check for power. If you get power, you've got a bum relay.
How do you test a 3 pin radiator fan switch?
1:445:39How To Test and Replace A Radiator Cooling Fan Switch - YouTubeYouTubeStart of suggested clipEnd of suggested clipWe have continuity. So the way that this switch works is once the coolant reaches around 200 degreesMoreWe have continuity. So the way that this switch works is once the coolant reaches around 200 degrees fahrenheit. This makes a connection inside the switch and we should have continuity.
How do you test a radiator fan circuit?
10:3017:52Overheating Help! | Testing Cooling Fans - Relays - ConnectionsYouTubeStart of suggested clipEnd of suggested clipSo you disconnected apply 150 ohms worth of resistance to the connector. Start the vehicle and thatMoreSo you disconnected apply 150 ohms worth of resistance to the connector. Start the vehicle and that will kick the high speed function on the fence.