Electric cooling fan does not come when the engine starts to heat up

Over heating the engine is a serious concern. With the hood raised you should hear the motorized fan turn on just behind the radiator as the engine requires additional cooling.. If you look in from the rear of the radiator you should see the fan blades.

This electric powered motor operates on a thermostat and when the engine temperature rises this fan should come on. I'm assuming from your description that when driving and air is flowing through the radiator as the car travels the engine is nor overheating.

Check fan motor thermostat, check fan motor and check wiring.

Wiring Diagrams related to the Honda Civic
http://www.wiringdiagrams21.com/category/automotive/honda-automotive/civic

Motor engine cooling fan only runs as engine temperature requires additional cooling.

Radiator Cooling Fans - Professional Mechanics Online

www.2carpros.com/articles/how-an-electric-cooling-fan-works

Aug 1, 2015 - Step 1 - There are primarily two types of engine radiator cooling fan, electric and manual. A manual fan is connected to the engine drive pulleys ...

article How a fan clutch works

https://www.2carpros.com/articles/how-a-clutch-fan-works

Sep 3, 2015 - Step 1 - A fan clutch function is to engage the fan blade to the shaft when heated which is mounted to the front of the engine attached to the ...

Improving an Engine Cooling Fan Using Design for Six Sigma

www.mathworks.com/.../improving-an-engine-cooling-fan-u...

MathWorksA key component of an engine's cooling system is the cooling fan, which ... a shroud to direct airflow through the radiator (image courtesy of Novak Conversions).

An overheating engine is more than a bummer, it can be an expensive engine killer that will leave you on the side of the road, then on to the repair shop for an expensive repair bill. If your car has been running hot, you know the feeling. You're sitting in traffic, the light turns green, and you pray that traffic breaks enough for you to get some air flowing over the radiator so that engine temperature needle will go down just a little bit. It's beyond stressful, and there's no reason you should be forced to endure this. The fact is, there are only a few things that commonly cause an engine to overheat regularly. 1. Low Coolant By a large margin, the most common cause for engine overheating is simply a low coolant level. Your engine's cooling system relies on coolant to circulate and remove heat from the engine. If you don't have enough coolant in there to do the job, heat will build up and your engine will overheat. No amount of running the heater in the summer will help if you don't have enough coolant in the radiator to transfer that heat. By far, the first thing you should do if your engine seems to be running hot is check your coolant level. 2. Electric Cooling Fan Failure If you have an electric cooling fan that isn't coming on, this can cause your engine to overheat. The electric cooling fan draws cooler air through your radiator when your car isn't going fast enough to ram it through from the front. You can test this by letting your car idle long enough for the engine to heat up. If you've been having an overheating problem in traffic, keep an eye on your temperature gauge. When it starts creeping into the danger zone, look under the hood to see if your electric fan is running. If it's not, you'll need to figure out why. There are two usual causes to this:
2a. Bad Electric Fan: Sometimes your fan motor will just burn out and your fan won't come on at all. To test this, find your radiator fan switch and disconnect the wiring harness. Get a jumper wire and insert it into both contacts, your fan should come on. Another way to test the fan is to turn on the air conditioning. Most, but not all, cars activate the cooling fan at either a medium or high speed when you turn on the AC.
2b. Bad Radiator Fan Switch: There is a switch that tells your cooling fan to come on when your coolant reaches a certain temperature. The easiest way to test this switch is to disconnect the wiring harness and then run a jumper wire across the harness contacts. If the fan comes on, you need to replace the switch. 3. Thermostat Not Opening The most common symptom of a failed thermostat is overheating at highway speeds. Your engine may be able to stay cool at low speeds because it's not working that hard, and therefore not creating as much heat. But at highway speeds your engine needs lots of coolant flowing through. If the thermostat doesn't open, there isn't enough flow to keep things cool, and you'll find yourself looking more like a steam ship than a sedan going down the highway. 4. Broken Fan Belt There are still lots of engines out there which have a fan belt to drive the engine cooling fan. If you see a belt attached to your fan, you're in this club. The good news is your repair is always cheaper than the electric guys. You can replace your fan belt easily if it's broken. 5. Clogged Radiator If your car has more than 50,000 miles on it, your radiator could start getting gummed up. You can avoid this and other problems associated with old coolant by flushing rad every year.

Your vehicle speed sensor is mounted in the transaxle housing which is also subject to heating and cooling. The wiring harness to and from the speed sensor is also subjected to engine heating and cooling. Anybody that knows anything about electrical circuits can tell you that an electrical circuit's worst enemy is heat. You need to diagnose the vehicle speed sensor circuits like the code is TELLING you to do.

The main cooling fan on this 1999 jeep cherokee, the main fan all depends.

These jeeps come with diffrent fan set ups. Here are a few, the first may be a fan driven off the motor by a fan belt and a another fan which is electric. the primary fan used for cooling is the fan that runs off the engine with a belt. the other electric fan is more the air conditioning system, this fan is used for cooling the condensor mainly. the engine driven fan is for the cooling system.


Another system fan set-up on these jeeps would be the motor driven fan by belt with another electric fan in front off it, the diffrence between the first and this one is that the first fan system is side by side and this one is set-up one in front of the other but the concept is the same, the fan driven by the engine is mainly for the cooling of the engine coolant and the electric fan is for air conditioning cooling.

In both set-ups the electric fans also help the cooling system but are mainly used for the help in cooling when the a/c is turnned on, the a/c condensor builds up heat the same as the radiator does, one fan is unable to cool both the radiator and the condensor, this is why some cars have two fans.

Good day, hope this is helpful,

If you replaced the thermostat I would look next at the electric cooling fan thermostat.. Its likely located in the radiator itself and is in charge of turning on the electric fans.

To check. start the car and listen for the fan next to the radiator to kick on. It should start running before the car gets over heated.

Also when the temp gets really high is the radiator hot? if not then you still have a coolant flow problem. If the radiator IS hot then you have a problem with the coolant not getting cooled. Either an electric fan/thermostat of if you have an engine driven fan maybe its clutch is bad.

try turning key on with out starting see if electric cooling fan comes on if not start engine turn on ac if it doesn't come on that's most likely the problem (fan,wire or sensor to the fan )

Odds are your electric cooling fan[s] isn't coming on. This fan should only run when the a/c is on or when the engine temperature has reached about 218 degrees. Once the a/c is off or the engine temp drops to about 210 degrees it shuts back off again. It rarely comes on at speeds over about 35 mph because at that speed enough air is forced through the radiator to keep the engine at about 198 degrees. I would start by looking for a blown 30 amp fuse under the hood. There may be two of them marked "Cooling fan 1" and "Cooling fan 2" or something similar. If the fuses are good you could have a faulty cooling fan motor that just isn't running. Hope this helps a bit!

I agree with philip, i have not studied the electrical system. but to my best guess the electric fans are tied into the engine cooling system. when the engine is not requesting the fans to come on. then their is very little air passing threw the cooling package. When their is no cool air passing by the condenser this will not draw the heat out of the refrigerant leaving excess heat in the system and when the cab fan blows this is were the excess heat is getting dumped. then at higher speeds their is enough air passing threw the condenser and radiator to cool them both.

Fifteen minutes! you have bigger problems than only the fans the fans are controlled by a thermo switch that is heated by the coolant, If you have no coolant the sensor cannot activate But fifteen minutes seems like you may have a headgasket problem and steam cannot heat the coolant sensor.OperationNotesThe electric cooling fan operates when the engine cooling temperature exceeds a certain value. The cooling fan on this engine is controlled by the Powertrain Control Module (PCM) . The PCM turns the cooling fan ON by grounding the coil of the cooling fan relays when certain conditions are met. When the A/C is requested, the cooling fan will also be turned ON.

Power for the cooling fan motors are supplied through Maxifuses(R). The cooling fan relays are energized when current flows from the fuses in the Underhood Accessory Wiring Junction Block, and through the relay coils to ground through the PCM. The Coolant Fan 1 Relay Control Circuit is grounded for low speed fans operation. During low speed fans operation, both fans run at a slow speed. The Coolant Fan 1 Relay Control Circuit is grounded for high speed operation. During high speed fans operation, both fans run at high speed.

IMPORTANT: When certain Diagnostic Trouble Codes (DTCs) are present, the PCM may command the cooling fans to run all the time. Perform the A Powertrain On Board Diagnostic (OBD) System Check prior to diagnosing the engine cooling fans.

For more information regarding the Charging System, refer to Charging System Description , and Charging System Circuit Description in Starting and Charging.

If a problem that involves the low speed cooling fan relay control circuit exists, DTC P0480 Cooling Fan Relay 1 Control Circuit should set. If the problem affects the high speed cooling fan relay control circuit, DTC P0481 Cooling Fan Relay 2 Control Circuit should set. A problem with the ECT sensor should set DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage, DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage, DTC P1114 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage, DTC P1115 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage. Any of these DTCs will affect cooling fan operation and should be diagnosed before using the Electric Cooling Fan Diagnosis.

For more information regarding the Cooling System refer to Engine Cooling Fan Description - Electric, and Cooling System Description in Cooling System.


Here is the electrical schematic and how it all is suppose to work,
If you need any further help please contact me Thank you,Randy If you find this information helpful please give me a good rating

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