Hello – in addition to the coolant temp sensor that triggers the cooling fan operation (so does the AC switch on most cars), the fans utilize one or more relays that route the power to the fan motor itself. Since you are able to make the fans run by bridging the sensor connectors, it seems likely that the coolant at the sensor is not reaching "trigger" temperature. You can check this with an infrared temp sensor o confirm either way. For assistance, I recommend a coolant fan inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
How to Identify and Fix Common car Problems ?
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Faulty temperature sensor
On most modern cars, the cooling fan is controlled by the Engine Control Unit (ECU) which gets a signal from the coolant temperature sensor. If it`s not working, the fan won`t turn on when it needs to, which means the engine might overheat.
1 Answer. The Fan Control Module is on the lower driver side of the radiator… Or it can be located on the driver side lower frame rail.” This is what it looks like (just a different number π Hope this helps, good luck.
The main fuse box is on the outer edge of the dash. Open the drivers door and you`ll see it. Remove the cover and you`ll find the fuse positions are all labeled on the cover underside.
The function of the cooling fan relay is to convert a low voltage signal from either the electronic control module (ECM) or a thermostatically controlled sensor. The cooling fan relay takes the low voltage signal and internally switches the relay βonβ to allow battery voltage to be supplied to the radiator cooling fan.
A malfunctioning coolant temperature sensor may send an incorrect βcoldβ signal to the ECU, tricking it into believing the engine isn`t hot yet. The ECU will then adjust the fuel injection, ignition timing, and variable valve timing, further raising the engine`s temperature and causing it to overheat.
Most electric cooling fans get their power from an ECM-controlled relay.
it lives underneath the frame rail directly under the battery.
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.
Check the Fan Fuse
Many fans β especially large, industrial-strength ones β are equipped with a thermal fuse for safety. Like the circuit breakers in your house, these fuses are designed to break the electrical connection when too much electricity causes your fan to overheat.
That`s perfectly impossible!! It`s as impossible as making your breakfast using a program without any hardware. Relay module can only turn things on or off. They can`t alter the resistance.
There isn`t one per se. There will be a fused wire with voltage to the instrument cluster (your owners manual should indicate which fuse), but the temperature sensor is providing a variable “resistance to ground,” which the temperature gauge in the dash is reflecting.
A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor) is used to measure the temperature of the coolant/antifreeze mix in the cooling system, giving an indication of how much heat the engine is giving off.
The engine-ECU <M/T> or engine-A/T-ECU <A/T> controls the fan controller to activate the radiator fan motor and the condenser fan motor.
The condenser fan relay is the electronic relay that controls the power to the AC condenser cooling fan. When the relay is activated the AC condenser fan is switched on so that it can keep the AC condenser cool.
To test the fan motor, you will need a multimeter. Set the multimeter to the ohms setting and touch the probes to the two terminals on the motor. If the reading on the multimeter is infinite, then this means that there is an open circuit and the motor is defective.
The fan control module can be located in a variety of places on the vehicle. The most common is on the radiator fan and condenser fan assembly as shown above. Other possible places are along the firewall of the vehicle or even under the dash.
Often, the only symptom of a blown fuse will be a small electrical problem in your Volkswagen. Maybe one of the interior lights won`t turn on, or the radio won`t work. These are relatively minor problems, of course–but a blown fuse could also make it so your car won`t start.
If the cooling fan motors burn out or fail, the cooling fans will be disabled. The cooling fan motors work together with the cooling fan blades to pull air through the radiator.
The black wire is the hot wire that leads to the switch. The white wire is neutral and completes the electrical circuit. Copper or green wire is the ground wire and keeps the fan from experience power surges. If there is a blue and black wire coming from the household circuit, there should be two switches on the wall.
If the fan doesn`t work, before pointing the finger at the blower motor, check fuses for the motor to make sure they`re still good. Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.
A fuse is always connected in the live wire of the circuit.
If the coil or contacts on the pump start relay are bad then the pump will not run. Likewise, if the irrigation controller is not sending that 24 VAC signal to the pump start relay, then the pump will not run.
Temperature sensor
The sensor reads the system`s temperature and determines when to turn the fan on. If it isn`t functioning properly, chances are that the fan won`t turn on, and the vehicle may overheat as a result.
An unlikely, but possible, cause is a bad thermostat. Try turning the Fan switch to the “On” position to see if the blower comes on. Watch the video. If the blower operates in the “On” position and does not operate when the air conditioner is running, you may have a bad thermostat.