Radiator Fan Relay | How to bypass Radiator FAN

In this video I am going to tell you about how to directly control the radiator fan of your car. this is an emergency procedure in case your radiator fans are not working. The radiator fans are controlled through relays in case the ecu si not sending signals to the relays or the relays are broken you still need your radiator fan for operating your car as it prevents your car from heating so you can directly connect the radiator fan for the time being untill you fix the original issue

Reasons Behind A Malfunctioning Radiator Fan
The most common reasons for a radiator fan not working can be a blown-out fuse, a bad relay, or a broken wire. The faulty coolant temp sensor might also be a reason behind it. Whatever the case, a dysfunctional radiator fan can be fatal. Let’s look at some of the most common causes.

Blown Fuse
All the electrical equipment has a fuse to cut off the input to the system to prevent it from malfunctioning. Similarly, in a car, too, a fuse supports everything electrical. The fuse cuts the electric supply to the component, which gets an energy surge and saves it from destruction. If this happens, rest assured that it’s the case of a faulty fuse.

A blown fuse shouldn’t concern you too much, and changing it is inexpensive. If your car radiator isn’t working, you might want to check the user manual and locate the fuse for the radiator fan. The fan uses a big fuse with a capacity of 50A, but sometimes the fan control module has another small fuse. If the fan’s fuse is faulty, you may have a problem with the wiring or the radiator fan itself.

Coolant Temperature Sensor
Modern-day cars come with two different systems in different car models. Some have fan controls integrated into the engine control unit, while others have a separate fan control module. Both systems use a temperature sensor to determine when to start the fan. If the temperature sensor is faulty, the control unit doesn’t interact with the radiator correctly.

Some cars have a separate engine coolant temperature sensor for the radiator fan and the engine control unit. You can measure the sensor resistance with a multimeter to ensure its functionality. The vehicle’s repair manual will help you better understand your car’s cooling system.

Wiring Problem
If the sensor and the fuse are working correctly, but the fan doesn’t turn on even when the car is overheating, it might be a wiring issue. Inspect the wiring going to the radiator’s control unit or the relay. Check connector plug health and see if they are corroded at the relay and the control unit. A multimeter might not be helpful as it only helps determine functionality when there is a load on the wires. However, if you want to check the power input to the radiator fan, this particular tool might help.

Low Coolant Levels
It is essential to check your coolant levels regularly and keep them at an optimum level. A low coolant level allows air into the system, and this causes the temperature sensor to act up. Low coolant levels cause the engine to overheat and sometimes seize. Repairing a seized engine might prove to be a costly affair.

Faulty Radiator Fan
The radiator fan works on an electrical motor that wears out after some years of regular use. If you have checked for all the factors mentioned above and the radiator fan still doesn’t come on, there might be a problem with the fan. To test the electrical radiator fan of your car, take a wire from the car battery, unplug the radiator fan connector, put 12v+, and ground it into the connector. This method is the fastest and easiest way to check the radiator for any faults.

Faulty Fan Relay
The cooling fan draws a low power and therefore comes with a relay. The relay is an electromagnetic switch that controls the power supply to the engine’s cooling fans. The relay is used to ensure that the energy-intensive components function when required. The relay powering the coolant fan can get damaged over time and cause the radiator fan to malfunction. You can check the engine bay’s fuse box to locate the fan relay for repairs.

Fan Controller Module
If the radiator fan’s control module is in the engine bay, it is susceptible to heat and dust. The exposure can make the control module fail after a while due to corrosion.