Consequently, if it does not spin it is blown. After several requests from members, thought I'd put it here for reference. Defective fan relay. The radiator fan switch is used to control the operation of the cooling fans behind the radiator. A fan failure; or a failure of the fan relay or control circuit is bad news; because it can allow the engine to overheat. At this point the fan should come on. The thermostat switch can be tested easily after it has been removed from the vehicle. The volt meter will then give you a voltage reading. ). In this test step, we're gonna' test all of the circuits of the fan relay by bypassing the radiator fan switch with a jumper wire. The radiator fan switch relay may not be supplying power to the fan. Locate the coolant temperature switch and unplug it. Testing LOW SPEED FAN This test is straight forward and is done with one press of a button! This is a DIY test with No T4 TESTBOOK required !! These switches open when the set temperature is reached thus turning the fan(s) on. Most fans should come on when the coolant reaches about 200 to 230 degrees. Turn on the burner and slowly increase the water temperature. The fan will then cycle on and off as needed to maintain the proper coolant temperature. If it spins more than three full rotations, this indicates that it may be prone to slipping. If the fan stops working, you can test the motorcycle fan switch and the fan simultaneously by bypassing the fan switch and hot-wiring the fan. So, engine coolant leaks can happen, anywhere in the cooling system. The switch has 92C/87C stamped on it so I assume it is supposed to turn on at 92C and off at 87C. Second, start the engine and start idling your vehicle. After confirming that the radiator fan relay is getting juice (TEST 1), the next step is to jumper circuits 1 and 2 with a jumper wire to see if the radiator fan motor comes on. So in order to how to check if radiator fan is working, you have to check the voltage of a few fuses in the under-dash fuse box (number 3, 15, and 20) and under-hood fuse box (number 47 and 50). I just replaced my fan switch with the Neuspeed 3 pole switch that brings the fans on at 80 degrees. If there’s an issue with the relay, the fan will be affected. How do you test the radiator fan relay switch on a 1999 plymouth voyager. Connect one end of the 12-gauge jumper wire to the black ground wire of the fan. TEST 2: Bypassing The Radiator Fan Relay. Unscrew the switch from the radiator (use an adjustable spanner) and then with it plugged into it's plug, rest the end on the exhaust manifold with it up to running temperature (you'll need to have a hose running through the header tank so it's got constant water). Print this page; Share this page × Ad. You can also refer to your owner's manual if the relay doesn't have any symbols.Resistance Test: 1. The radiator fan should spin. Normal voltage for a radiator fan is around 12 volts. When the coolant temperature hits a certain point, it causes the switch to turn the fan on, which in turn reduces the coolant temperature. I put it in a pot of water and monitored temperature and resistance as the water heated. Double check your test connections and repeat the test once again. Set the … On applications that have variable fan speeds; the engine may also overheat if fan speed fails to increase when additional cooling is needed. The first step is checking for a blown fuse. 1 Answer. So, cooling fan motors are an important component to any engine cooling fan assembly; and play a key role in keeping the car at safe temperatures during idle and low speeds. After confirming that the radiator fan relay is getting juice (TEST 1), the next step is to jumper circuits 1 and 2 with a jumper wire to see if the radiator fan motor comes on. You should read infinite resistance. Another easy test is to see if the motors work. Use the volt meter to test if there is power to the wires. The drawback to water-cooled systems is that the thermostat, thermostat fan switch and the fan itself must all work together to keep the system from overheating. Step 2. If one spins a lot shorter ammount of time it could mean it’s either dead or on it’s way out. The first components that should be tested are the cooling fan, the cooling fan relay and the thermostat switch, which turns the fan on and off depending on the temperature of the engine. In conclusion. Hydrolocked Engine – What Is It – What Damage Can It Do, Engine Coolant Temperature (ECT) Sensor – Function – Failure And Testing, The (ECT) sensor, is an engine management system sensor; that is used to monitor the temperature of the engine’s coolant. Want Answer 0. So, The fan runs mostly at idle or low speed when the engine is at normal temperature. Locate the positive and negative wires on the cooling fan. First, you need to connect your test light to the battery ground. Older cars have glass; cylinder-shaped fuses with stainless steel on the ends and glass in the middle. If The Fuse Is OK Move On To The Next Step. HOW TO TEST RADIATOR FAN SPEEDS FROM TRINARY SWITCH (DIESEL CDT/i, 1.8 & KV6 Variants. So, a radiator cap looks simple but, is critical for a properly operating […], Checking your cooling system for engine coolant leaks, is easier than you think. For more information about how to test a fan clutch, such as other signs to look for which indicate damage, read on. Bypassing The Radiator Fan Relay. That may be all you need to get back on the road. Be sure you have the right one. If it does not, check to see that there is current flowing to the switch by using a … Fortunately, nine out of 10 times, engine coolant leaks are easy […]. Since the fan motor isn't activating on its own... the next step is to check the radiator fan motor switch. If the resistance does not change to zero, then the switch is bad. Comment; Flag; More. CASE 2: The radiator fan motor DID NOT come on. The cooling fans should turn on when the sensor in the bottom passenger side of the radiator detects that the coolant temperature has exceeded 172°F, or when the air conditioner is turned on. It was a git of a job. The ohmeter should be turned on and have a reading of high resistance. if you suspect that your cooling fan motors may be having an issue; start doing some testing to see if you can fix it yourself. Refer to the top or side of the relay to locate these terminals. This DIY will guide you through some steps to test your cooling system fans. At times, your cooling fan stops working because a sensor has gone bad, but the fan works just fine. I want to make it clear this test isn’t going to give you a definitive answer but it can help to point you in the right direction. The Next Thing To Test Is The Coolant Switch Or Sensor, (ECT) Engine Coolant Temperature Sensor – What Can Go Wrong, Radiator Cap – Basic Function – Failure Symptoms – How Important Is It, Engine Coolant Leaks – How To Find Them – How Bad Are They, 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, Valve Lifters – Hydraulic And Mechanical – What Is The Difference, 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, Engine Coolant Temperature Sensor (ECT) Replacement – How To Do It, Defective temperature switch; coolant sensor or other sensor, Engine thermostat is stuck OPEN (engine never gets hot enough to turn on the fan), A wiring problem (blown fuse, loose or corroded connector, shorts, opens, etc. Make up some jumper cables; connect them directly from the battery to the fan motor to see if it spins. To check this, unplug the single wire connector and, using a jumper wire, ground it. Place the thermostat switch in the sauce with the terminals turned up. You will now place the red probe on the common wire. Copyright 2020 Leaf Group Ltd. / Leaf Group Media. Be sure you have the right one. Test The Radiator Fan Temperature Switch . The fan relay controls the power to the cooling fan. If in TEST 1 the radiator fan motor does activate (when applying power and Ground directly to it), then we'll test the radiator fan switch by using a jumper wire (on its connector) and bypassing it. COPYRIGHT © 2020 DANNYSENGINEPORTAL.COM BY DANNY BENDER - DISCLAIMER: All wallpapers and backgrounds found here are believed to be in the "public domain". The fan may work but it only runs at low speed; which may not be fast enough to prevent overheating. If the resistance does not change to zero, then the switch is bad. If It Is Working; Move On To The Next Step. The fan should 'ramp-up' from 0 to 100% and back to 0% speed. Connect one of the ohmmeter probes to one of the thermostat terminals and connect the other probe to the second thermostat terminal. Step 5. Place a small sauce pan on the stove and fill it with one cup of water. Consequently, Some vehicles have as many as three; One for a dashboard warning light William Kinsey lives in Concord, N.C. This switch is configured to work based upon the temperature of the engine. Electric radiator fans operate when radiator temperature rises to preset heat range. You just need to know the correct steps. Most Japanese cars have a normally closed switch. Adding a manual switch to an electric radiator fan is an economical way of keeping your car cool and in good condition. Faulty wiring could be to blame. The switch is essentially a thermostat that senses the temperature of the coolant. If the volt meter reads 12 volts, the problem is not the power and the fan needs to be replaced. STANDARD RELAY PINS 30: Constant 12V, unswitched 85: Signal (switched … For this test, the only tool that you need is a test light. Watch this video to figure out how to diagnose problems with the cooling fan relay on a Chrysler. Your engine cooling fan will not work if you have a blown fuse. Kick off the engine or switch the ignition key off to IG2. The old 4 wire motors have quite a short life and fail between 60 - 80k miles. The best way to test it is to bypass the fan's normal circuit and straight wire the fan to the engine. If the fan motor now works, the switch is faulty. Basically all you have to do is spin the fan blades and see how long they keep spinning. Turn on the burner and slowly increase the water temperature. He currently holds a Bachelor of Science in electrical engineering from the University of North Carolina at Charlotte and a Master of Business Administration from the University of Phoenix. The tip of the (ECT) sensor protrudes into one of the cooling system passages; and […], Today the radiator cap, is more important than ever before. For this test, go to: TEST 2: Bypassing The Radiator Fan Motor Switch. Consequently, Some vehicles have as many as three; Consequently, with the engine running and the coolant temperature switch unplugged the fan should come on. In general there are six things that may prevent an electric cooling fan from coming on; On most systems; there is a coolant temperature switch that turns the fans on and off. If necessary, a replacement relay costs around $20.There are three ways to check for a bad terminal. If the fan motor is not at fault, leave the ignition switched on, take the connections off the thermo-switch and briefly touch them together. In general; most vehicles on the road have two types of fuses. TEST 1: Checking The Radiator Fan Relay Power Circuits. TEST 2: Bypassing The Radiator Fan Relay. If your fans are not running when they should (or are running when they shouldn't), these steps will help locate the problem. We do not intend to infringe any legitimate intellectual right, artistic rights or copyright. It may cause the fan to cut in and out, or not come on at all. Bypassing The Radiator Fan Switch. Step 2. Bypassing The Radiator Fan Switch. When the water reaches between 180 to 220 degrees Fahrenheit, the switch should turn on and the resistance seen by the ohmmeter should change to zero. Step 4. Posted by walter graves on Oct 05, 2012. Using a multimeter is another good way. Stephen . So, If you find a blown fuse replace it. The temperature switch on most vehicles is typically connected to your car computer, or your powertrain computer. If you're rusty or new to this automotive element, here's a short rundown of how radiator fans work. On most systems; there is a coolant temperature switch that turns the fans on and off. 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. TEST 2: Bypassing The Radiator Fan Motor Switch. When the water reaches between 180 to 220 degrees Fahrenheit, the switch should turn on and the resistance seen by the ohmmeter should change to zero. I am getting ready to put my re-cored radiator in the car and decided to check the thermal radiator fan switch before reinstalling it. Place the thermometer in the sauce pan so you can read it as the temperature increases. A wiring issue. Locate the coolant temperature switch and unplug it. Cut both wires and strip 1/2 an inch of insulation off of the ends of the two fan wires. Set the ohmmeter to the lowest range. Protects relay from arcing damage due to fan spinning after shut-off. However, it is often overlooked, as being a cause of engine overheating. If it doesn’t, and you have a domestic vehicle; the coolant temperature switch is a normally open type that stays open until the coolant reaches its set temperature. MVB -137 will show you some AC system status/request info. 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. Unplug the Fan Connector closest to the fan. When it reaches that temperature; the switch closes and turns the fan(s) on. The switch is located about 2/3 of the way down the end of the radiator. The ohmeter should be turned on and have a reading of high resistance. The (PCM) will now detect a failed switch; store a Diagnostic Trouble Code (DTC) and turn on the fan(s). A way to get around this situation is to wire in an on and off switch. 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. Step 1. Then test the fan clutch by giving it a good push. The easiest way to check it is; visually check it for a continuous wire with no breaks. Connect one end of the volt meter to a ground and the other end to the electrical connection on the fan. As engine temperature rises to a specific threshold, the switch is activated powering on the coolant fan. Extra cooling is not needed when a cold engine is first started; so the engine cooling fan does not come on until the engine reaches normal operating temperature. Most newer cars have a different style of fuse that uses a plastic housing; with the fusible link encased in the housing. This is a very simple test but you do need to take one very important precaution and it's to use a small diameter jumper wire (gauge-wise). This is the detailed process of how to diagnose an overheating problem (Radiator Fan not working) on a 1997 Honda Civic. Values measured in this phase of testing should be around fifteen ohms. When the radiator temperature lowers to a preset level, the electric fan turns off. Test the third set of wires: With the negative black multimeter test lead still on the brown wire, take the red test lead and take it off of the white wire. ADJUSTABLE FAN SWITCH WITH RADIATOR PROBE (GROUND SWITCHING, NON-VARIABLE SPEED ONLY) 30-40 AMP FAN 1 FAN 2 HAYDEN 3653 PN: IN5408 Make sure the diode band is facing toward the fan or relay and away from ground. He also currently owns and operates Sophisticated Curves, an online fashion mall that caters to the needs of plus size women. Testing requires only a few minutes and a few tools. Bypassing the radiator fan switch. The process of wiring this switch is relatively easy. He started writing articles in March 2009, which have appeared on Autos.com and CarsDirect.com. Connect the leads of an ohmmeter to the power terminals on the relay. Defective fan control module; The Next Thing To Test Is The Coolant Switch Or Sensor. See the Tips section at the bottom for more information. He also has several years experience as an outside plant engineer and planner with AT&T. NOTE: You can modify the above tests to suit your particular diagnostic needs. Battery out including the box, intercooler pipe off, map sensor disconnected, wiring moved and a deep 30mm socket from Halfords to loosen the switch. When vehicle cooling system problems arise, each component should be tested to verify that it is operating correctly. Replace it and you are back on the road. Clicking this will make more experts see the question and we will remind you when it gets answered. Level 3: An expert who has achieved level 3 by getting 1000 points. If the fan clutch requires repair, take the vehicle to a qualified mechanic. This switch works by eliminating the ground connection when it is switched "off" and reconnecting the ground when it is "on". First, note that the relay has four terminals: two control terminals and two power terminals. 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