Solved: engine cooling fan

Showing posts with label engine cooling fan. Show all posts

Thursday, November 29, 2012

Chevrolet Engine cooling fan not running

Cooling fan not running on Chevy cavalier

The engine cooling fan not working causing engine to run hot, but fan does operate when defrost or a/c are used.

So i don't think fan is actually the issue.

UNDERSTANDING OF THE PROBLEM:----
The fan turns on when A/c or heater is turned ON, the engine temperature will sit where it is supposed to.
I.E. it does not run hot as long as the fan is on.

but if the A/c is not turned ON then fan will not come ON and engine overheats.

See below the wiring diagram for cooling fan:-----

The fan turns on via air conditioning or via coolant temperature.

So its coming on with A/c and heater turned on,but not coming on when the coolant temperature gives the command.

The fan is controlled by same relay and same fuse to turn on,whether its by A/c or coolant temperature.

And now when we know that fan is running when command is from A/c so its clear that fuse and relays are working fine.

Both the ac position and the coolant temperature sensor sends signal to ECM(Computer) to turn on the fan, then the engine computer sends that signal to the relay

So now its confirmed that relay or fuse is extremely unlikely to be the issue

The problem is most probably the coolant temperature sensor, the alternative would be a faulty engine control module or faulty wiring between the coolant temperature sensor and the engine control module.

If you notice CHECK ENGINE LIGHT COMING UP ON DASH,then most likely its faulty coolant sensor.But if No check engine light then issue will be mostly the faulty ECM( Computer module).

See below the coolant sensor location diagram for your Chevy model:----

These details will help.
Thanks.

Main radiator cooling fan is not working

Ford Cooling fan not working

A/C fan runs but Engine cooling fan (the radiator one) is not running.

Ford Edge 2007 V6 model:

On most of such cases the problem is related to faulty cooling fan module.Its a costly part about $700 to $800.

But before getting the module directly replaced get the module tested first :----

The module is not getting a good ground and there is high resistance.Causing the module to fail.
The module is not getting good power and its running at lower volts than needed.
One of the fans has high resistance and is overheating the fan module.Can also short the fan module.

]What i suggest you to do is rewire the connections directly from 12 volt source.

Directly wire each fan separate to power and ground and use an ammeter on the wires to see if one fan is drawing more amps than the other.
Then OHM test your ground to the module while the fans are being used. Then voltage test the power while both fans are being used.

To test these i provide you the fan and fan module wiring diagram for ford edge:----

radiator fan wiring diagram

IMPORTANT NOTES THAT YOU FOLLOW WHILE PERFORMING THE TESTING:----

With both fans running check the power at the fan module it should be 12.6 volts or near to that.This indicates that the fans are getting required voltages power. If its very low then replace the wire.

Now again with both fan running check the resistance to ground at the module. There should be no resistance to ground, if there is then replace the wire or check the wires connection to ground.

Main testing rewire the fans directly to the battery.Because battery is main 12 volt source and fan needs basic 12 volt to function and run. After both are running and have been for a bit check the made power wire to see how many amps both fans are drawing. They should not be over 20 amps. If they are then the fan is bad.And has to be replaced.

These details will help.
Thanks..

Engine Cooling FAN NOT WORKING

Radiator fan not working

Chevy Cavalier Cooling fan not working

Fan will not run with A/C ON or Heater ON.

With no fan running in ac or heat up its :

bad fan motor
bad relay
bad fuse
or bad ECM (computer module)

Fuse located under hood.Cooling fan fuse number 30 AMP.
To confirm the fault you need test-light

First i suggest you to remove the fan relay from under hood fuse box. Then turn key on. Now with the test light you need to probe the terminals. Need power on 2 of them. If no power? then fuse if power on 2? then possible relay.

Now reinset relay in, get engine hot and turn ac on.
Probe the light blue wire to fan. if power? bad fan motor. if no power? back to relay or even failed ECM.

so if relay is not problem, fan motor not problem, fuse is good then have to suspect bad ECM and yes., it can happen

To confirm the fault go through wiring diagram shown below:-----

under hood fuse box,
cooling fan relay and the 30 amp fuse for cooling fan
its a max fuse or one of the larger ones

engine cooling fan wiring

These details will help.
Thanks.

Wednesday, May 30, 2012

1998 Mercury Mystique: Engine cooling fan not Running?

After driving for few minutes the engine overheats and fan should come ON.But out of two fans only one comes up and other engine cooling fan not coming up and also A/C is not working.

It can be Faulty cooling fan or its the issue with Engine cooling fan Relay.

But before replacing the relay, unplug the wiring harness connector to the engine fan and do 2 things.

First, run jumper wires from the battery to the cooling fan to make sure that the fan runs and hasnt failed due to a short in the harness.

Next, you need to carefully check the harness connector where you thought you saw scorching and see if any of the wires are melted or if connector is melted, allowing the wires to touch and short out and if found, repair the wires.

If all is ok and fan runs, then in the fuse/relay box in the engine compartment, swap out the cooling fan relay(highlighted in yellow) with another relay to see if the fan comes on:

The Relay diagram is shown below:----
Engine cooling fan relay

To jump the wire from battery to fan motor.

You will need a couple of long wires that both ends are stripped to expose the wires. Connect one to the positive end on the battery and one to the negative. Then touch the other ends to the 2 terminals on the fan motor connection terminals on the fan itself(where harness connector plugs into).

You do have to use caution to prevent from shocking yourself by touching the ends of the wires. If not comfortable doing this, then you want a friend with mechanical experience to do this or have a mechanic do this.

This details will help.
Thanks.

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Saturday, February 25, 2012

How to replace engine Cooling Fan Switch?

Cooling Fan Switch Operation:

The cooling fan switch on electric fans monitors coolant temperature signals from the engine control computer. When the engine is cool, the switch opens to keep the fan from spinning. When engine is warm, the switch closes to turn fan on for cooling.

See below how the cooling fan looks :---

Before replacing cooling fan switch .Inspect and tst it.

Inspect the cooling fan switch's wires and connections. Cooling fan switch problems are often caused by faulty wiring or loose or corroded connections rather than the failure of the switch itself. If the wires or connections are bad, replace them. If you think the switch is defective, it should be tested.

Also listen for a pinging noise, failed cooling fan switches can cause pinging when the engine is overheating.

Test :--

When testing a cooling fan switch, first test it with the engine cold, then test it when the engine reaches a specified temperature. Check your vehicle's service manual for more directions.

To check a switch, disconnect the connector at the switch. with an ohmmeter, check for continuity between the terminals of the switch with the switch moved to the on position and to the off position.

The continuity through a switch can be checked with an ohmmeter. With the switch open, there should be infinite resistance. With the switch closed, there should be zero resistance.

With the switch off, there should be no continuity between the terminals. With the switch on, there should be good continuity between the terminals. If the switch is activated by something mechanical and doesn't complete the circuit when it should, check the adjustment of the switch. (Some switches are not adjustable.) If the adjustment is correct, replace the switch. Another way to check a switch is to simply bypass it with a jumper wire. If the component works when the switch is jumped, a bad switch is indicated.

Voltage drop across switches should also be checked. Ideally, when the switch is closed there should be no voltage drop. Any voltage drop indicates resistance and the switch should be replaced.

Replace cooling fan switch :--

Because of the variations of electric cooling fan systems, manufacturers' schematics and specifications must be consulted for troubleshooting and repairing any particular year-model car.

CAUTION

Some fan motors will start, and run, without warning even though the ignition switch may be in the OFF position. Therefore, extreme caution should be exercised when working under the hood of a vehicle equipped with an electric cooling fan.

To replace the switch:

Disconnect the negative battery cable.

Unplug the cooling fan switch.

Then, unscrew it.

Reverse the removal procedures to install the new part.

Connect the negative battery cable to the battery.

This will help

Thanks.

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