The reading should match the battery voltage. [1] By using our site, you agree to our. Ratchetsand Wrenches assumes no liability for any property or personal damage that may arise from doing a repair on your vehicle after watching any of my repair video's. You should see or hear the continuity indicator from the meter. We use cookies to make wikiHow great. What do I do if all the indicators on my relay don't work? Current transformer: One of the most common forms of current sensor is referred to as a current clamp. A relay will have several connections; two of these will be the two ends of the coil. Check if they're blown out visually - coil running across would be cut or split. Information on current and voltage ratings, pin configurations, and other information is sometimes available in the datasheets will be invaluable in testing, and eliminate most errors associated with testing. Extra low voltage work typically will not fall under this requirement, but it's still important to be safe. Testing Coil Relays Determine the coil requirements of the relay. This article has been viewed 707,363 times. Take a multimeter and place the knobs on continuity checking mode. Probe the main wire leading from the relay with the test light. Look at the readout on the multimeter’s screen to see if it reads 0, meaning the circuit has no resistance between the points. Generally there are two types of transformer in the market i.e. Approved. Include your email address to get a message when this question is answered. ", "This article has been very valuable in helping me diagnose a relay problem with my truck. IV. By far, the easiest way to test a suspect fuel pump relay — or some other automotive relay — is to swap the suspect relay … All the NC contacts should read 0 ohms, or 0 resistance, while the NO contacts should read infinite resistance. the linear type and the switch mode power transformer. Check resistance of the coil. https://www.explainthatstuff.com/howrelayswork.html, http://www.autoshop101.com/forms/hweb2.pdf, https://www.ccohs.ca/oshanswers/safety_haz/electrical.html, https://robrobinette.com/Tube_Amp_Safety.htm, https://www.electronics-tutorials.ws/io/io_5.html, consider supporting our work with a contribution to wikiHow. (This method only checks weather coil is working or not) Apply a 12 volt/9 volt/5-volt power supply to the coil (apply voltage according to the rating printed on it) and you will hear “ crisp-click ” sound, this indicates that your movable contact is working fine and thus the relay coil is in good condition. Some relays, depending on their size, may also have this information printed directly on the body of the relay as well. If you want to test a coil rely, make sure there is no power going to it, then use a digital multimeter to test the resistance between each of the relay’s poles and their NC and NO contacts. Turn or press your vehicle’s ignition to Accessory. If your multimeter doesn’t have a dedicated continuity setting, you can still perform a continuity test by turning the dial to the lowest number in resistance mode. Set the multimeter in continuity test mode. The Fastest Way to Test a Fuel Pump Relay or Other Automotive Relays. How do you check the continuity of a coil relay? % of people told us that this article helped them. To test a relay to see whether it is good or defective, the simplest way to do would be to use a multimeter set to the ohmmeter setting and measure various resistance values of the relay. "Thanks, even I was in the dark about checking relays - must be the old school in me. wikiHow marks an article as reader-approved once it receives enough positive feedback. Fuses. If the wire lacks continuity, it has a "short." How to Test a Relay. the relay cover may pop off without damage. If so, the coil should be good. If you don't, switch the meter to 'Resistance' or 'Ohms' (the Greek symbol for omega) and see if you have somewhere between 0 and maybe 100 ohms between the coil contacts. Check the continuity, if yes the N/c pin works properly. ", "I have a report and I stole this idea from here.". A second, more exact method requires special instruments and a power source. This is basically a fast switch on a much faster switch that can turn off and on, which fail often due to temperature fluctuations. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/d\/d2\/Test-a-Relay-Step-1-Version-2.jpg\/v4-460px-Test-a-Relay-Step-1-Version-2.jpg","bigUrl":"\/images\/thumb\/d\/d2\/Test-a-Relay-Step-1-Version-2.jpg\/aid1420038-v4-728px-Test-a-Relay-Step-1-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"