What should the radiator fan be running at?

The fan continues to run at its maxiumum speed, regardless of the engine temperature. I allowed the car to run today from cold to just above 80 deg. C before sutting it off today.

Why is my Mercedes radiator fan running on high speed?

Please try again later. This is a very common problem with the Mercedes radiator cooling fan running constantly on high speed. The problem in most cases is a bad ecm so in order to fix it the ecm will have to be replaced and programmed to work with your vehicle. Check the mass airflow sensor first.

What causes radiator to overheat at high speeds?

Starts to overheat when outside temp over 90 degrees. Shut A/C off engine temp comes back down.. Mostly in traffic or slow speeds. At high speeds no problem with temp. Check you radiator fan clutch, it is activated by a sending unit and temp sensor.

Why is my air conditioner fan running at high speed?

This problem is often caused by a faulty pressure sensor located on the air-conditioning condenser. If accessing fault codes, there are no relevant DTCs stored in the engine control module (ECM) or signal acquisition module (SAM). • Run a Quick Test to check for any relevant fault codes.

The fan continues to run at its maxiumum speed, regardless of the engine temperature. I allowed the car to run today from cold to just above 80 deg. C before sutting it off today.

What happens when the radiator fan burns out?

If the cooling fan motor burns out, the cooling fans will then, in turn, be disabled. Since the cooling fan motors work in tandem with the fan blades to pull air through the radiator, the blades will then not be able to spin or cause any airflow to cool off the car.

Why are my cooling fans running at all times?

3. Cooling fans stay on at all times. If the cooling fans are staying on at all times, this is another (less common) symptom of a possible problem with the cooling fan relay. If the relay shorts internally, it may cause power to be permanently switched on, which will cause the fans to run at all times.

Can a bad fan relay cause an engine to overheat?

However, a bad cooling fan relay isn’t the only culprit for excessively high engine temperatures. Many other issues can cause the engine to run hot or overheat. Rather than uncommonly high engine temps, the driver may notice that the cooling fans have stopped running.

Why is my radiator fan not turning on?

The computer sends power to the relay to activate it and turn the fan on. Once activated, however, if the relay sticks in the closed position then the fan will run until the battery is totally discharged.

Why does the radiator motor not work on a 2006 M35?

On some 2006 M35/45 vehicles, the radiator fan motor may begin to operate incorrectly or not operate at all. If this occurs, in certain limited circumstances, the engine control logic may temporarily reduce engine output in order to protect against overheating damage.

Why are the cooling fans running on my Infiniti M35?

Forum for Infiniti M35 and M45, and Nissan Fuga owners. I noticed the other day when I pulled my 06′ M35X out of the garage the cooling fans were running which I thought odd but blew it off.

Where is the coolant fan relay located in a 2001 C320?

My 2001 C320 was overheating. After reading here, and doing some diagnostic work, the fuse was a little burnt. Replaced that, and still no luck. Then I did the A/C trick, and the fan came on, but at slow speed. So I’m guessing it’s the temperature sensor or the relay. Process of elimination, where is the relay?

Why does my car’s radiator run so fast?

I’m not a Benz mechanic so what I’m stating is from an experience I had on my 2008 C300. Two things will make your radiator fan run on fast. Either a signal that the engine is hot or that the air conditioning condenser (located in front of the radiator) is telling it that it’s hot and to run fast to cool it down.

Why does my C300 4Matic run full speed?

I am a new owner of a 2010 C300 4Matic that I bought from an insurance auction – the car was a salvage car due to a front impact. I have repaired all of the damage, but there is one issue that I cannot figure out. Immediately upon starting the car, the radiator fan begins to run full speed, even though the car is stone cold. The AC is OFF.

How can I tell if my radiator fan is working?

When a radiator fan works it usually makes a whirring sound that is easily noticeable. However, the radiator fan does not always start spinning on ignition. The ECU signals the radiator fan to work at the precise time. So, do not worry if the fan doesn’t immediately start working. Visually check the fan if you don’t hear its noise. 1. Broken Fuse

Why does my car have a radiator fan?

You probably already know the purpose of the radiator and the cooling system in your car. When you are driving fast, the wind is passing through the radiator to cool the coolant down without issues, but when you are driving slow, there is no wind pushed through the radiator. This is why we use a radiator fan.

Where is the relay on a radiator fan?

The fan relay is often located in the engine bay’s fuse box, but the best way is to check your repair manual to find where it is located. Testing a 4 pin relay is often very straightforward. Remove the relay and give 12 volts to pin 30 and 85. Ground pin 86 and check if there is voltage coming out from pin 87.

Is it normal for a car fan to run all the time?

This is normal in many vehicles, such as BMW or Mercedes-Benz. The radiator fan may run up to five minutes and sometimes longer. Unless there is an electrical issue, it may stay on all the time until it drains the battery. When the engine is running, the coolant circulates from the engine and flows to the radiator, where heat is dissipated.

Is it OK to leave the cooling fan on when the engine is turned off?

Car Fan Still On When Engine is Turned Off You park your car, turn off the ignition and start walking away. Then you notice the engine cooling fan is still running even though the car is turned off. It is ok for the engine cooling fan to keep running for a few minutes after turning off the car.

Why is my radiator fan running so slow?

The problem is most likely one of three things: a low coolant level, a bad coolant sensor, or the thermostat needs to be replaced. The only other possible thing it could be is a bad BCM (Body Control Module) which in that case you would most likely be having other weird problems.

Why does the radiator cooling fan not stop when vehicle is shut?

As some point along her 20 mile trip the radiator cooling fan came on. I thought this was odd due to the air temperature. At stops the engine shut off as expected. Cooling fan continued to run. When she arrived at her destination she turned the vehicle off. Cooling fan continued to run. She called me.

Can a car fan still run after the engine is turned off?

Then you notice the engine cooling fan is still running even though the car is turned off. It is ok for the engine cooling fan to keep running for a few minutes after turning off the car. Your car fan will run for a few minutes after you turn off the car then turn off. This is normal in many vehicles, such as BMW or Mercedes-Benz.

How often does a car cooling fan stay on?

Cooling fans stay on at all times Average rating from 129,472 customers who received a Vehicle Engine Cooling Inspection. Most modern vehicles use electric cooling fans to help pull air through the radiator so that it can keep the engine cool.

What should I do if my fan is running at a constant high speed?

Confirm that there are no leaks at the sensor, that the air-conditioning is operating as expected and that the fan no longer runs at a constant high speed. Finally use the AssistPlus to run a Quick Test and ensure there are no new fault codes.

What should the fan pressure be at stand still?

For example, at a coolant temperature of 51.0°C (123.8°F) the refrigerant pressure should be no more than 12 bar. If it is higher, the air-conditioning control module presumes that the pressure is high and assigns the fan control module to run at 90% PWM actuation. Also check the AAC pressure at stand still / cold.

How to troubleshoot your Mercedes medic air conditioner?

Turn the A/C ON. If you have an Economy button make sure that is off. Make sure fan is on HIGH, temperature selector is turned all the way to COLD, and that the A/C and recirculate light indicators are on. Set the temperature to cold, the lowest setting. Set the cooling fans on high on the climate control.

Which is the hot side of the radiator?

When one feels the upper radiator hose (driver side), it is HOT, and the air blowing near that side of the radiator appears to be hot. The lower radiator hose (passenger side) is COLD, and the air blowing near that side of the radiator appears cool. The heat is also turned on full blast, and blows lukewarm/cool air.

How does Mercedes Benz air conditioner system work?

While the pictures on this article are of Mercedes Benz cars, this guide is written to apply to all makes and models. How the A/C System Works. A/C compressor not engaging.

What are the signs of a bad cooling fan?

Common signs include the engine running hot and cooling fans either not functioning or running all the time. 1. Engine running hot 2. Cooling fans do not function 3. Cooling fans stay on at all times Most modern vehicles use electric cooling fans to help pull air through the radiator so that it can keep the engine cool.

Why does my radiator fan turn on and off?

A mechanical fan WILL spin as long as the engine is running, but it will only ‘lock up’ when needed. Furthermore, why does my radiator fan turn on and off?

When does the cooling fan come on or off?

I’ve read that the cooling fan will run the whole time when either the A/C is on or the vent control is set to defrost, regardless of whether the engine is cold or hot. In my case, the cooling fan comes on when the engine is cold, even with the HVAC off and it will remain running at full speed when the engine is running, again with the HVAC off.

What does it mean when your radiator fan is not working?

This is what we call a blown fuse. A blown fuse is no big deal, and changing one does not cost a lot of money. If your car’s radiator fan is non-functional, check your car’s user manual and locate the fuse for the radiator fan controller or the fan.

How much does it cost to replace a radiator fan?

A mechanic would initially check all the other things related to the radiator fan to make a proper analysis. A radiator fan is not very expensive and can cost around $200 – $400. It’s the fan motor that makes the radiator expensive. Your mechanic would charge you $120 to $200 depending on the make and model of your car and the nature of the work.

Is there a way to test a radiator fan?

You can test the electrical radiator fans by taking a wire from the car battery, unplug the radiator fan connector, and put 12v+ and ground into the connector. This is the fastest and easiest way to test your radiator fans. Because the radiator fan is often drawing so much power, there is often a relay that is powering the coolant fan.

Why is my engine cooling fan running at constant high speed?

There is no Schraeder valve on the sensor and removing the sensor allows the gas to escape into the atmosphere. Replace the sensor and confirm good location of the wiring connector. Locate wiring in order to avoid chafing of harnesses. Use the AssistPlus to check the reading in the climate control module.

Can a broken radiator fan keep your car cool?

A radiator fan has an important role of keeping a vehicle’s engine cool. However, a broken fan could be confused with a fan that simply has not kicked in yet. This is one reason why information on when a radiator fan is suppose to start can be beneficial to vehicle owners. Temperature will often determine the time that a radiator fan starts up.

How does a fan motor work on a radiator?

In this arrangement, when the fan switch is operated, B+ voltage is applied to the fan motor via a relay whose control power (coil power) source is the ignition bus. So the fan will go off with the ignition regardless of the position of the control switch, yet the fan current is still supplied by the battery bus.

What happens when a radiator fan is disengaged?

When radiator discharge air is below a certain temperature, the coupling remains disengaged. According to Hayden Automotive, a typical disengaged coupling will run the fan at 30% to 50% of its input rpm.

What should I do if my radiator fan is not working?

A blown fuse is no big deal, and changing one does not cost a lot of money. If your car’s radiator fan is non-functional, check your car’s user manual and locate the fuse for the radiator fan controller or the fan. The fan itself often uses a big fuse of around 50A, while there might also be a separate small fuse to the fan control module.

Why do you need a radiator fan in a car?

To stop the engine from overheating, we take the help of coolants that flow through a radiator into the engine. The radiator’s job is to keep the coolant cool so that when it returns back into the engine, it is able to absorb more heat. A radiator fan is thus used to keep the temperature of the coolant in check. Thus, it has an important job.

Can a 3 wire radiator fan run when unplugged?

Use the one for the older cars. Your car is old enough to use a F129, four wire double switch, not the 3 wire G65. It should not run when unplugged. You can safely short (jumper pin to pin on the connector) a 4 wire switch for testing.

What to do if your computer cooling fan won’t run?

Replace the cooling fan relay with a new one. A stuck closed relay is the only thing that can operate the cooling fan continuously with the key off. The computer looses power with the key off and the same applies to the coolant temperature sensor. The relay, however, has direct power to one side, the same as a light switch.

How does a high speed fan control relay work?

When the engine temperature reaches 200 degree’s the PCM energizes 1 to 3 Cooling fan relay’s in the battery junction box (fuse-relays ) The low speed fan relay , High speed fan control relay 1 , an high speed fan control relay 2 . Now what problem are you having ?

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