In most cases, their diagrams are right from the factory manuals. This is a generic powertrain diagnostic trouble code (DTC) applicable to most 1996-newer vehicles. This is a generic powertrain diagnostic trouble code (DTC), which means it covers all makes/models, 1996-newer. - The A/C clutch requested. Set the … Verify the battery positive terminal in the relay block with constant power. So you have to refer to the factory legends to learn the identification symbols and then refer back to circuit diagrams to find the splice and ground locations. It is not intended as repair advice and we are not responsible for any actions If swapping relays still doesn't operate your cooling fan, make sure the relay is receiving power from the computer. - The vehicle speed is less than 38 MPH. There are multiple factors that can lead to this error code. The operating components in the cooling fan circuit include the cooling fan fuse, relay, coolant temperature sensor and the computer. Open or shorted fan cooling fan harness 5. When you bring the car to a stop no air is passing through the radiator and the engine begins to increase in temperature. The fan that is not in front of the air conditioning condenser is the main cooling fan and the one to concentrate on initially. Do not go any farther without consulting your service manual. This is also a good idea before buying a vehicle. Probe the sensor terminals. 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. Jump the battery terminal to the fan harness terminal and the fan will operate. The opposite side goes to the fan. NOTE: This information is presented for information purposes only. The relay is regulated by grounding the control circuit via the driver or the internal switch, a process which is entirely controlled by the ECM. The radiator fan switch relay may not be supplying power to the fan. Multiple factors can lead to this error code, some of the most common possible causes are: 1. A/C selector switch 9. If you need to dig into your doors, dash or console, Alldatadiy.com is the better choice because Eautorepair.net doesn’t any interior or exterior trim or body part removal. 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. With this sort of an illustrative manual, you’ll have the ability to troubleshoot, avoid, and complete your assignments without difficulty. Contact Us Open or shorted fan control relay harness 2. The activated relay completes a circuit, allowing an electric current to flow through it and reach the cooling fans. Defective coolant temperature sensor 7. They include wiring diagrams and technical service bulletins. Related. - The vehicle speed is less than 38 MPH. Check it with the ohmmeter, there should be a big change in resistance, if not the sensor is bad. The PCM (powertrain control module) senses the increase in engine temperature through the CTS (coolant temperature sensor) located near the thermostat. The first part of the installation is to install the electric fan to your radiator, and remove the mechanical fan. If the fan operated, check the relays. That saves a lot of time because you don’t have to refer back to the component locator or circuit locations. Repair if necessary and use dielectric grease on the terminals. Search using your favorite search engine "technical service bulletins for ....." Look up the code and the type of manufacturer recommended repair. Open or shorted fan cooling fan harness 3. Poor electrical connections in the cooling fan circuit 6. A switched terminal will be hot only when the key is on. Defective faulty fan control relay 1 2. But other Chrysler and Dodge vehicles use a more traditional radiator fan relay. Specific repair steps can vary from make/model. See the schematic printed on the relay itself or consult the schematic in your vehicle repair manual, if necessary. Open the hood and do a visual inspection. You can also refer to your owner's manual if the relay doesn't have any symbols.Resistance Test: 1. Additionally, many vehicles have multi-speed fans requiring as many as three fan speed relays for low, medium and high. Use a test light to find the hot terminal. P1491 Radiator Fan Control Relay Circuit P1491 Radiator Fan Control Relay Circuit. Most modern vehicles use electric cooling fans to help pull air through the radiator so that it can keep the engine cool. Alldatadiy.com, on the other hand, uses the factory diagrams. Pull the connector apart and look for corrosion or bent pins. When coolant temperature rises above acceptable limits, the computer provides ground to the fan relay. When the PCM attempts to activate the fan and senses the command and the result do not match, the code is set. If not, disconnect the fan connection at the fan and using an ohmmeter check the continuity between the fan side of the relay terminal and the connector at the fan, If there is continuity the fan is bad. The PCM controls the cooling fan by grounding the cooling fan control circuit which turns ON the cooling fan relay. 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 temperature reaches about 223-degrees F (value depends on make/model/engine), the PCM will command the cooling fan relay to turn on the fan. Use an ohmmeter to test that the constant battery terminal and the fan harness terminal have continuity meaning the circuit has closed. What does that mean? Look at the circuit diagram displayed on the side of the relay. Pull the connector off. Check all the relays in the same fashion to be sure they are all working. Electric Fan Relay Wiring Diagram– wiring diagram is a simplified tolerable pictorial representation of an electrical circuit.It shows the components of the circuit as simplified shapes, and the capability and signal contacts between the devices. A duty cycle is determined based on these input parameters. Faulty VSS (vehicle speed sensor) This is a generic powertrain diagnostic trouble code (DTC), which means it covers all makes/models, 1996-newer. Any one know where the thermostat or temp switch for the control circuit is? Attach the fan to the small area around the core Of the radiator where there is a metal lip that is approximately 1/4" to 3/8". If necessary, a replacement relay costs around $20.There are three ways to check for a bad terminal. 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. All content © 2004-2021 OBD-Codes.com, Cooling fan 2005 Chevy Tahoe 5.3L p0480 [Solved], 2000 Olds Silhouette p0131, p0137, p0480, p0742 + more, 2005 Chevy Trailblazer Ext P0480 wont start, post The schematic will help you also when checking the fan cooling circuit. Look at the side of the relay for the switched power terminal or just turn the key on. 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. Published by Saum Hadi. The PCM controls the cooling fan by grounding the cooling fan control circuit which turns ON the cooling fan relay. Let the engine cool and put the ohmmeter on the 200,000 scale. However, specific troubleshooting steps will vary depending on the vehicle. ground switched device using a simple spst relay. Eautorepair.net redraws factory wiring diagrams in color and includes the component, splice and ground locations right in their diagrams. The reading will be about 2.5. However, Alldatadiy.com also includes disassembly instructions for interior trim panels and exterior items like headlights and tail lights. - The A/C clutch requested. Open or shorted fan control relay harness 4. Shut the engine down and pull the CTS plug again. It is a generic code applying to all OBD II (on board diagnostics) vehicles. If there was no switched power at the relay, the ignition switch is suspect. The PCM controls the cooling fan by grounding the cooling fan control circuit which turns ON the cooling fan relay. Disconnecting the PCM could cause loss of programming and the vehicle may not start unless towed to the dealer for reprogramming. It is a generic code applying to all OBD II (on board diagnostics) vehicles. If you’re tracking down a wiring issue, Eautorepair.net is the better choice. your question in our FREE car repair forums. A/C refrigerant pressure sensor 10. Look at the fan and make sure there is no obstruction in front of the radiator blocking airflow. adjustable fan switch/thermostat with built-in relay and radiator probe (12v switching, non-variable speed only) 86 30 87 85 5 amp fuse signal circuit 12v switched (ignition or fuse panel) power “on” when key is in the “run” position. A malfunctioning cooling fan relay can … Check the terminals for an additional power terminal and look where it would be on the relay. The cooling fan relay coil receives the Ignition Voltage directly. DIAGNOSTIC TROUBLE CODE (DTC) - P0481 HIGH SPEED COOLING FAN RELAY CIRCUIT FAULT (WITHOUT A/C) Details of the Circuit. The fans that are used to cool the engines radiator are run by electric motors. your question in our FREE car repair forums, Check engine light (malfunction indicator lamp) illumination and code P0480 set, Engine temperature will rise when the vehicle stops and idles, Fan control relay harness is open or shorted, Fan cooling fan harness is open or shorted, Cooling fan circuit poor electrical connection. This will allow mounting of the fan(s) without compromising the core of the radiator. All information on this site is copyright protected. Pricing: ---Eautorepair.net--- 1 month subscription $19.95 per vehicle 1-year subscription $29.95 per vehicle 4-year subscription $44.95 per vehicle ---Alldatadiy.com--- 1-year $29.95 subscription: additional vehicles $19/95 each 5-year $49.95 subscription: additional vehicles $34.95 each Which one should YOU choose? Refer to the top or side of the relay to locate these terminals. Recently, I was driving my 2015 Jeep Wrangler JK Unlimited through a parking lot on a 95 degree day, and after leaving a stop sign, a check engine light flashed on (later I would learn it was a P0480 Cooling Fan Relay 1 Control Circuit), and shortly thereafter my Jeep overheated. The cooling fan relay is the relay that controls the engine’s cooling fans. The vehicle computer monitors coolant temperature with a sensor located near the thermostat. (Please call for fan shroud suggestions). Faulty cooling fan 3 5. If the circuit has not closed or the relay has not clicked, the relay is bad. The cooling fan relay is an electromagnetic switch that controls the power supply to the engine’s cooling fans. For precise readings consult a service manual. A/C selector switch 9. Electric fan is responsible for causing air movement around the engine coolant radiator. There is a problem within this circuit causing the fan to fail to operate allowing the engine to overheat while sitting still or driving at a slow speed. If they prove to be good, check the CTS with an ohmmeter. A code P1492 indicates a problem with the relay circuit. In the Painless Performance electric fan relay kit we got from Speedway Motors, a circuit breaker is supplied if you wanted to safely get power directly from the battery. If they are good pull the cooling fan relays out. The ground completes the circuit to the relay and switches power to the fan. + + this will be your new ground switched output. Step 1 - A relay is used to control (switch) a high amperage electrical circuit with a low amperage one, for example a radiator fan can pull up to 25 amps when in use, which would burn the computer circuit that controls it, a relay is used to bridge this circuit to prevent electrical damage. Video on how to diagnose dtc p1491, radiator fan control relay circuit malfunction on a 2003 jeep liberty sport. A/C refrigerant pressure sensor 10. Open the fuse block and inspect the cooling fan relay fuses. Most late model vehicles use an electric fan to pull air through the radiator. If you still need help regarding the P0480 trouble code, please post Anyone know where the relay for the cooling fan is? Radiator fan relay switch wiring electric override electrical diagrams how to replace a cooling fan relay on most vehicles 2002 dodge caravan cooling fan relay wiring 2016 grand 2006 ford escape fuse diagrams ricks auto repair. The fan as well as other apparatus draws too much amperage to be safe in the cockpit, so it's kept under the hood. By using a lower voltage signal to control the relay, there is less stress on the rest of the wiring and charging system. you take on any vehicle. While you are driving, air in sufficient quantity is passing through the radiator effectively cooling the engine. If you have a P1491 Radiator Fan Control Relay Circuit trouble code, this post will help you understand what it is and how to fix it. However, specific troubleshooting steps will vary depending on the vehicle. Jump the battery plus terminal in the first test with this switched terminal and place an additional jumper from the negative terminal on the relay to ground. NOTE: P0480 speaks of the basic circuit, however codes P0481, and P0482 relate to the same problem with the only difference is they relate to the different fan speed relays. Look for the simple open and shut circuit. Faulty cooling fan 1 3. If not the harness between the fuse block and the fan is faulty. Most late model vehicles use an electric fan to pull air through the radiator. First, note that the relay has four terminals: two control terminals and two power terminals. A relay kit, our part number CCFKRL, will include everything you need to properly wire up your electric cooling fans, with the exception of additional wiring needed to complete all of the circuits. The fan relays are nothing but a remote light switch. The amount of air movement caused by the fan is controlled based on the Vehicle Speed, coolant temperature, A/C pressure status, A/C switch request status, and A/C clutch state. - The vehicle speed is less than 38 MPH. Faulty VSS (vehicle speed sensor) The bottom of the fuse block lid will usually indicate placement, but if not, look in the owner's manual. - The A/C clutch requested. If you have a P1491 Radiator Fan Control Relay Circuit trouble code, this post will help you understand what it is and how to fix it. The negative terminal in this circuit is the one used when the PCM wishes to active the relay by grounding it. Accuracy isn't necessary since all sensors may be different. There must be a relay that the control circuit closes, this relay may be welded closed or the control circuit is telling the cooling fan to run. It does so by supplying the ground to the relay. Mount the fan as high up on the core as possible. This one turns on the fan when the circuit is closed. IAT (intake air temperature) failure 8. 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. This tutorial will help you to diagnose the Pulse Width Modulated (PWM) fan relay on the 1999-2003 Jeep 4.0L Grand Cherokee SUVs and/or the codes P1491 (Radiator Fan Control Relay Circuit).The dealer, at the time of this writing, will charge you $95 (US) to diagnose it. Defective or faulty fan control relay 3 4. (adsbygoogle = window.adsbygoogle || []).push({}); While you are driving, air in sufficient quantity is passing through the radiator effectively cooling the engine. cooling fan relay wiring diagram – You will need a comprehensive, expert, and easy to understand Wiring Diagram. A constant power supply from the battery is present on a terminal in each of the relays. If the above procedure could not find a failure, the probability is that a poor connection to the PCM or the PCM itself is at fault. It is always a wise idea to look up the technical service bulletins (TSB) on your particular vehicle to see what type complaints have been coming in to the dealer service department related to this code. Cooling Fan 3 Relay Control Circuit High. The switch will click on. If it will not spin the fan bearings are shot and the fan is bad. Dodge Radiator Fan Wiring Diagram. 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. Reconnect it and warm the engine. Check the electrical connection at the fan. You just want to know if it's working. When … Spin the fan with your finger (make sure the vehicle and key is off). Some of the most common possible causes are: 1. Until such time as you can either complete your checks of the circuits or take the car to a service facility, pull the fuse in the fuse relay … The vehicle's PCM's function is to act as a ground to operate components, not to supply power. Many vehicles will have two engine fans, one for engine cooling and the second for cooling the air conditioning condenser, and additional cooling for the engine. Defective coolant temperature sensor 7. Most cooling fans use electric motors that have a moderate to high current draw, and as a result are commonly controlled using relays. 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Speed is less stress on the relay computer monitors coolant temperature sensor and the computer, which means it all... No air is passing through the radiator effectively cooling the engine ’ s fans. The one to concentrate on initially control the relay block with constant power supply from battery... Medium and high farther without consulting your service manual same fashion to good! When the circuit to the component locator or circuit locations block with constant power supply to the engine cool the. Compromising the core as possible ’ re tracking down a wiring issue, Eautorepair.net is the one concentrate..., make sure the vehicle to locate these terminals circuit p1491 radiator fan coil! On initially wiring diagram is set the owner 's manual if the circuit has closed... If they prove to be sure they are good pull the cooling relay! Necessary since all sensors may be different and charging system power terminals re down! The switched power terminal and look for corrosion or bent pins are nothing but a remote light switch or of... And Eautorepair.net are professional-grade shop manuals—period there should be a big change resistance.