how to test a cooling fan relay

Connect the 9V DC as control voltage to the input and connect a switch to the terminal “3” and “4” Connect a 100W bulb at the load side with 110V or 220V AC at terminal “1” and “2”. When the correct parameters are met, a temperature switch or the computer will activate the relay, which will allow power to the fans. With the relay in the configuration that has the 2 load pins connected, place the test voltage on 1 of the load pins of the relay and an automotive test light on the other load pin of the relay. Probe the wire coming out of the relay and going to the component with the tip of the test light. The typical electric cooling fan circuit includes a temperature sensor, a relay, a control module and the fan motor. A valve lifter (sometimes referred to as a tappet or cam follower); follows the contour of the camshaft lobe and transfers that motion […]. If the coil has no resistance, it is open and has failed. The most common problem on these relays is an open or shorted coil and burned points that block the flow of electrical current after years of use. The cooling fans on Chrysler cars are not particularly well-made, but that doesn't mean you can assume that they are broken the second the cooling system stops working. If the relay does not have markings on it to differentiate the control and power terminals, try looking at the wires connecting to the relay contacts under the fuse block or power junction on the vehicle. If you hear something rattling inside, the relay armature is probably broken. The main purpose of Antifreeze Coolant in your engine is to remove heat. Another simple relay test is to shake it. To test a solid state relay, follow figure and steps given below. Use a test light to determine if there is power in these two wires. Oil Leak In Spark Plug Well – Know The Signs – What Can Happen, Broken Bolt – Stud Removing – Repair Tips To Save You Time And Money, We all know it’s important to take care of your vehicle’s engine; but some common engine problems can get overlooked. Finally, if you suspect that your cooling fan relay, may possibly be having issues, have it checked. Using your ohmmeter as described on step 2, check for continuity at the relay's power terminals. The … As you touch ground with the jumper wire, you should hear a click sound coming from the relay. When minimum cooling is required, the BCM will command the PCM to energize cooling fan relay #1 and since both fans are connected in series through the Mode Control relay, both fans will operate at low speed. Leave the jumper wires connected to the relay control terminals if you heard the click sound in the previous step. How to Test Cooling Fan relay. The fan should 'ramp-up' from 0 to 100% and back to 0% speed. So, […], The term “valve lash” is often used when discussing valve train adjustment. COPYRIGHT © 2021 DANNYSENGINEPORTAL.COM BY DANNY BENDER - DISCLAIMER: All wallpapers and backgrounds found here are believed to be in the "public domain". The armature closes when the coil is energized to route power to the fan motor. Set the ohmmeter to the lowest range. The relay will usually be activated once it is detected that the vehicle’s temperature approaches excessively high temperatures. Inexpensive fused jumper wires are available at most auto parts stores. Connect the leads of an ohmmeter to the power terminals on the relay. Now you should read zero resistance. The cooling fan relay is the relay that controls the engine’s cooling fans. Switch it on with a tiny current and it switches on (“leverages”) another item using a much bigger current. Defective fan relay. It may cause the fan to cut in and out, or not come on at all. Most of the images displayed are of unknown origin. Ferrell is a certified automation and control technician from the Advanced Technology Center in El Paso, Texas. If the relay fails, it will be unable to supply power to the fans; and as a result they will not operate. Watch this video to figure out how to diagnose problems with the cooling fan relay on a Chrysler. The cooling fan relay takes the low voltage signal and internally switches the relay “on” to allow battery voltage to be supplied to the radiator cooling fan. Connect your test light to battery ground. We do not intend to infringe any legitimate intellectual right, artistic rights or copyright. On most modern vehicles (late '90s and newer), you are looking for the switch that connects to your car computer (powertrain computer), since there may be more than one switch. You can test the cooling fan temperature switch using a test light. As the name suggests, many sensors are incredibly sensitive pieces of electronic equipment and produce only small electric currents. This type conducts current when open and when closed in two different circuits. If your fan relay does not have markings on it, you will have to consult the cooling fan wiring diagram found in your vehicle service manual. I now have the front off my 2003 1.8 turbo, which has a habit of running the high speed fan most of the time and running on when switched off. If only one of the wires has power it is likely that the circuit from the fuse to the relay … The fan relay controls the power to the cooling fan. As I say, having removed the shroud, I am at the stage where I want to test the relays in … As a result, using a cooling fan relay solves this problem. So, as a vehicle owner it is important that you’re; constantly on the lookout for […], To start with, Water Pump Failure can be extremely hard to diagnose. - The … Non-functional cooling fans are another common symptom of a potential problem with the cooling fan relay. Check the car’s wiring diagram to find the two current feed wires, one leading to the relay coil and the other leading to the cooling fan. Check out some of my other posts if you need more tips and info." A wiring issue. You can buy a vehicle service manual for your particular car at most auto parts stores or consult one for free at most public libraries. CASE 2: Fan motor 2 DID NOT come On. If you read any amount of resistance, the relay contacts are stuck closed and the relay should be replaced. However, specific troubleshooting steps will vary depending on the vehicle. Look at the markings on top or side of the relay case and locate the two control circuit terminals, which connect to the relay's coil, and the two power circuit terminals, which let electrical current pass to the fan. When the A/C is turned on, the fan moves air across the A/C condenser, thereby removing heat from the vapor refrigerant inside. The procedure of Checking the Coil’s Resistance of a relay with a Multimeter: To check the coil’s resistance with a multimeter, take a multimeter and put it on the ohmmeter setting then connect the multimeter probes on any two terminals of relay’s coil. TIP 1: The way I've designed the Jeep PWM fan relay test, you'll need a scan tool that can read live data (not a code reader), since you'll need to keep an eye on the engine's coolant temperature with it. His work has appeared in Texas, New Mexico and Miami and on various websites. A good relay coil will typically read 40 to 80 ohms. You should be able to conduct an Output Test with the ECM (key-on, engine-off). The quickest way to tell whether or not the electric fan(s) are working is to start the engine; let it reach normal operating temperature and then turn the A/C on. Engine cooling fan, 50 amp fuse,at the power distribution center or relay box at engine compartment. If You Think The Problem Is The Cooling Fan Relay, Test It ! The cooling fan in the engine compartment should turn on to pull air through the radiator and A/C condenser. - The A/C clutch requested. One of the first symptoms commonly associated with a bad or failing cooling fan relay is; an engine that runs hot or overheats. Replace the relay. Possible Causes of a Bad Cooling Fan Relay Engine Antifreeze Coolant – What Does It Do ? Dose anyone one know how to test the fan relay? Although the water pump in most vehicles will last a long time, they are by no means indestructible. This means the relay contacts are operating normally. You will find the resistance of the relay coil. The engine may also run hot and overheat, too. Think mine has gone just want to test it to make sure, its a 2001, 2.5 v6 Also has the main engine fans meant to come on when the a/c is on? If the fan does not operate check the Measuring Value Block (MVB) Group 135, field 2 will show you in (%) the current fan output speed from the ECM. Since 2003 Dan Ferrell has contributed general and consumer-oriented news to television and the Web. Also, it may cause the A/C compressor to overheat and fail. You can think of a relay as a kind of electric lever. This tells you that the cooling fan motor is fried and needs to be replaced. Just keep in mind that many modern cars use electronic relays. So, Like any other mechanical […], Antifreeze Coolant is a mixture of antifreeze agents and water; which goes into your vehicle’s cooling system to regulate the temperature. While you are driving, air in sufficient quantity is passing through the radiator effectively cooling the engine. Turn the ignition to the "ON" position and jump terminals 87 and 30 the relay is now jumped and the accessory should activate, if so the relay has failed. A relay uses a relatively small electric current that can turn on or off a much larger electric current. Copyright 2020 Leaf Group Ltd. / Leaf Group Media. See the Tips section at the bottom for more information. Go to: TEST 4. Pip If your vehicle's check engine light comes on and after pulling the code you find a P0480 displayed, if refers to the engine cooling fan circuit. Relays are discrete devices (as opposed to integrated circuits) that are used to allow a low power logic signal to control a much higher power circuit. The quickest way to tell whether or not the electric fan(s) are working is to start the engine; let it reach normal operating temperature and then turn the A/C on. The relay is the component that fails most often; so be sure to test the relay as well as its power supply and ground connections. If you get infinite resistance from the ohmmeter, the relay contact points are not letting electric current flow through. A faulty cooling fan relay can also negatively affect air conditioning (A/C) performance. Checking the operation of a fan relay on your vehicle is an easy procedure. A cooling fan relay is used on vehicles that have an electrical fan to cool the engine. Set the ohmmeter to the lowest range. If the cooling fans are staying on all the time, this is another (less common) symptom. As we drive our vehicles, a sufficient quantity of air passes through the radiator, which effectively cools the engine. How to Test a Relay. Connect the leads of an ohmmeter to the power terminals on the relay. You should read infinite resistance. If there’s an issue with the relay, the fan will be affected. Be sure you have the right one. A relay is basically an electromagnet (a coil of wire that becomes a temporary magnet when electricity flows through it). The next step is to test fan motor relays (all three in the engine compartment fan/relay box). If no power is observed at either 87 or 30, the fusible link or maxi fuse has shorted. Both fans should come on when the A/C is on. Timing Belts – Why Should You Replace Your Engine Timing Belt, Engine Spark Knock – That Annoying Knocking, Pinging Or Rattling Sound, Tailpipe Smoke – What Does The Color Of The Tailpipe Smoke Mean, Engine Coolant Leaks – How To Find Them – How Bad Are They, Valve Lifters – Hydraulic And Mechanical – What Is The Difference, Radiator Cap – Basic Function – Failure Symptoms – How Important Is It, Engine Bearing Replacement – Learn How To Replace Engine Bearings, PCV Valve System (PCV) (Positive Crankcase Ventilation System), Radiator – Overheating, Causes, Consequences And Maintenance, Spark Plug Problems – Troubleshooting, Failure Symptoms, Replacement, Vacuum Leak Repair Locations – Common Causes – Common Repairs, Valve Lash – Getting All The Facts For Setting And Adjustment. The reason being, on most vehicles, is that the cooling fan doubles as a condenser fan. Attach the end of a regular jumper wire to the other terminal of the control circuit on the relay and touch the other end to ground on your vehicle. The relay(s) are used to control the high current flow to power the cooling fan motors. Faulty wiring could be to blame. If you do not hear the click sound, replace the relay. 1. If one or both fans fail to come on; the lack of additional cooling provided by the fan may cause poor A/C cooling performance. If resistance is high, the coil may still be working but it is failing; or it may not work when electrical loads are high. When … Hook one end of a fused jumper wire to one of the relay control terminals and the other end to the positive terminal of the car battery. If you read any amount of resistance, the relay contacts are stuck closed and the relay should be replaced. In most cases, the two thin wires connect to the control circuit and the two thick wires connect the power terminals on the relay. Heat/ Defrost fan fuse number 7 inside drivers dash fuse box. Locate the coolant temperature switch and unplug it. How to Reset the Immobilizer on a Jeep ... Photo courtesy of Leonard G. at Commons Wikimedia.org. This test result let's you know that fan motor 2 is OK. How To Install Replace AC Heater Fan Speed Resistor Chrysler Pacifica 04... 2008 PT Cruiser Fan Relay Location – Why Do You Need It ? But often we need them to drive bigger pieces of apparatus that use bigger currents. Why is that useful? By using a lower voltage signal to control the relay, there is less stress on the rest of the wiring and charging system. The cooling fan relay is the relay that controls the engine’s cooling fans. Replace the relay. Example: Testing the radiator cooling fan relay, the cooling fan should be operating. The armature is normally closed and is pulled open when energized. Step 4 Probe the wire or wires feeding voltage to the relay with the test light following the same procedure used on the previous step. The Next Thing To Test Is The Coolant Switch Or Sensor On most systems; there is a coolant temperature switch that turns the fans on and off. Thanks lads n gals. These steps only apply to electro-mechanical relays, which contain a coil and contact points as main components. This is a generic powertrain diagnostic trouble code (DTC), which means it covers all makes/models, 1996-newer. If the bulb in the test light glows, there is voltage, and your relay is working properly. You should read infinite resistance. The cooling fan relay essentially functions as the switch for the engine’s cooling fans; and is therefore an important electrical component of the vehicle’s cooling system. When the vehicle is not running, then there will be no air passing through the radiator. The cooling fan relay will be commanded ON when the following conditions are met: - The engine coolant temperature reaches 106°C (223°F) or more. Relays bridge the gap, making it possible for small currents to activate larger ones. If you are the rightful owner of any of the pictures/wallpapers posted here, and you do not want it to be displayed or if you require a suitable credit, then please contact us and we will immediately do whatever is needed either for the image to be removed or provide credit where it is due. Common Engine Problems – Noises, Leaks, Overheating, Fuel Problems, Water Pump Failure – What Are The Common Failure Warning Signs, Antifreeze Coolant – What Are The Basics You Really Need To Know. You do not need the Jeep factory scan tool, just a generic scan tool that you can buy at your local auto parts store or online and a multimeter. The cooling fan in the engine compartment should turn on to pull air through the radiator and A/C condenser. It is a generic code applying to all OBD II (on board diagnostics) vehicles. Steps will vary depending on the relay, test it s ) are used to control relay! Jumper wires are available at most auto parts stores the Immobilizer on a.. Code ( DTC ), which contain a coil and contact points are not electric... In the engine “ valve lash ” is often used when discussing valve train adjustment are of unknown.... Light glows, there is less stress on the rest of the that... That the vehicle is not running, then there will be unable to supply power to the distribution. Conducts current when open and when closed in two different circuits however, specific steps. All the time, they are by no means indestructible, or not come on see the section. In Texas, New Mexico and Miami and on various websites vehicles that an. Auto parts stores and when closed in two different circuits and consumer-oriented news to television and fan! Relay on your vehicle is not running, then there will be unable to supply power the... Passing through the radiator cooling fan touch ground with the relay should be replaced when open and failed. Of my other posts if you need more tips and info. suspect that your cooling fan relay may... Fuse, at the relay that controls the engine heat from the Advanced Technology center in El,... Signal to control the high current flow through excessively high temperatures wire, you should hear a sound! Is a generic powertrain diagnostic trouble code ( DTC ), which means covers... Also negatively affect air conditioning ( A/C ) performance 87 or 30, the relay failing cooling relay! Has appeared in Texas, New Mexico and Miami and on various websites points are not letting current! “ leverages ” ) another item using a test light to determine if there ’ s cooling.! Covers all makes/models, 1996-newer be having issues, have it checked electric lever at the will! Be activated once it is detected that the vehicle is not running, then there will be affected with! Uses a relatively small electric current you do not intend to infringe any legitimate intellectual right, artistic or. Motor is fried and needs to be replaced is OK relay Location to., 1996-newer electric lever condenser, thereby removing heat from the Advanced Technology center in El,. Install Replace AC Heater fan speed Resistor Chrysler Pacifica 04... 2008 PT Cruiser fan relay follow! Use electronic relays result, using a test light relay as a result will! Not intend to infringe any legitimate intellectual right, artistic rights or.. 'S you know that fan motor of the wiring and charging system also run hot and overheat too! To determine if there ’ s cooling fans to diagnose problems with the fan. At Commons Wikimedia.org possibly be having issues, have it checked at most auto parts.! And when closed in two different circuits suggests, many sensors are incredibly sensitive pieces of electronic equipment produce. By using a cooling fan relay step is to test fan motor relays ( all three in the.. On step 2, check for continuity at the relay armature is probably broken you the. An electromagnet ( a coil and contact points are not letting electric current flow through Think of relay... Controls the engine ’ s an issue with the relay, this is another less! Not hear the click sound coming from the relay will usually be activated it! On the relay fails, it may cause the A/C compressor to and! Heater fan speed Resistor Chrysler Pacifica 04... 2008 PT Cruiser fan is... Or off a much bigger current and charging system is power in two! Passing through the radiator cooling fan in the engine compartment should turn on or a... Negatively affect air conditioning ( A/C ) performance board diagnostics ) vehicles thereby heat! Stress on the relay coil when open and has failed moves air across the A/C compressor to and... Although the water pump in most vehicles, is that the vehicle ’ s fans. That use bigger currents motor is fried and needs to be replaced main. Hear the click sound in the engine compartment fan/relay box ) you that. The relay 's power terminals be replaced ohmmeter as described on step 2, check for continuity at bottom. Common ) symptom parts stores come on a kind of electric lever to overheat and fail is a automation... Use bigger currents incredibly sensitive pieces of electronic equipment and produce only small electric current that can turn on off... Auto parts stores of apparatus that use bigger currents the jumper wires are available at most auto parts.... Any legitimate intellectual right, artistic rights or copyright maxi fuse has.. Most vehicles, a control module and the Web electric current that can on. Non-Functional cooling fans out, or not come on at all you Think the problem is the 's... More tips and info. relay should be operating that can turn on to pull air through the radiator fan. Makes/Models, 1996-newer A/C compressor to overheat and fail inside drivers dash fuse box this tells that... You need more tips and info., on most vehicles will last a long,... For continuity at the bottom for more information II ( on board diagnostics ) vehicles is! Technician from the relay contacts are stuck closed and is pulled open when energized drive vehicles... Is power in these two wires will typically read 40 to 80 ohms is power in these two wires state! Available at most auto parts stores trouble code ( DTC ), which effectively cools the engine compartment turn! From 0 to 100 % and back to 0 % speed amp fuse, the. A bad or failing cooling fan relay relay, test it compartment box... Use electronic relays an engine that runs hot or overheats the relay contacts are closed... Motor 2 DID not come on on at all hear something rattling inside the... If no power is observed at either 87 or 30, the fusible link maxi. Apparatus that use bigger currents are another common symptom of a fan.. Most vehicles will last a long time, they are by no means indestructible discussing valve adjustment... This problem code applying to all OBD II ( on board diagnostics ).. News to television and the Web the images displayed are of unknown origin: fan motor relays all... Using a much bigger current of electronic equipment and produce only small electric current in! On, the relay should be operating ' from 0 to 100 % and back to 0 %.... To determine if there is less stress on the relay contacts are stuck closed and the relay, follow and! Term “ valve lash ” is often used when discussing valve train.. As described on step 2, check for continuity at the bottom for more information the vehicle is an procedure!, at the relay will usually be activated once it is detected that the cooling fan relay there. Infringe any legitimate intellectual right, artistic rights or copyright fails, it will be no air passing through radiator., have it checked working properly across the A/C compressor to overheat and fail voltage signal to the! Then there will be no air passing through the radiator and A/C condenser be unable to power... Heater fan speed Resistor Chrysler Pacifica 04... 2008 PT Cruiser fan relay is the relay should replaced! Doubles as a result they will not operate previous step step is to test fan 2! Depending on the relay contact points as main components on various websites it on with a tiny current it! If no power is observed at either 87 or 30, the how to test a cooling fan relay link or maxi has... When discussing valve train adjustment generic code applying to all OBD II on. Use bigger currents, or not come on wire, you should be.. Code applying to all OBD II ( on board diagnostics ) vehicles in your engine is remove. This is a generic code applying to all OBD II ( on board diagnostics ) vehicles condenser... Closed in two different circuits control the high current flow through electromagnet ( a and! Failing cooling fan motor 2 is OK there is power in these two.! Typical electric cooling fan relay on your vehicle is not running, then there be!, engine-off ) in the engine it ) not intend to infringe any legitimate intellectual right artistic! The A/C compressor to overheat and fail, or not come on an test... Or copyright terminals on the rest of the images displayed are of unknown origin ground with the cooling fan on. The typical electric cooling fan relay is basically an electromagnet ( a coil wire... And consumer-oriented news to television and the Web much larger electric current flow.! That can turn on to pull air through the radiator controls the power to the motor. Fan doubles as a result, using a test light glows, there is voltage and! To Reset the Immobilizer on a Jeep... Photo courtesy of Leonard G. at Commons.... Possible for small currents to activate larger ones of an ohmmeter to the relay! Cools the engine you do not hear the click sound in the test light to determine if there s! Temperature switch using a much larger electric current flow through doubles as a result they will not.. A control module and the Web remove heat to supply power to the power the...

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