How to test radiator fan

jjklongisland

Registered User
I realized that now my fan is not kicking on at all. What is the best way to test to see what the problem is. I looked in the repair manual and do not notice any dedicated fuses for the fan. I tried researching the forums but couldn't find what I was looking for.

thanks
 
Unplug the ECT connector - near the A/C, over the front of the pass. side valve cover... Engine running - fan should run.

Also, when testing the codes, running the fan is one of the first things that should occur as part of that process.

As well, pushing the A/C button and turning the key on etc. should result in the fan coming on....A/C off and it should stop after a few moments.

And there is the direct test where you pull the connector at the fan, determine which wires are which, and then hot wire long enough to test. Don't energize the low and high circuits at the same time.
 
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Unplug the ECT connector - near the A/C, over the front of the pass. side valve cover... Key on - fan should run.

Also, when testing the codes, running the fan is one of the first things that should occur as part of that process.

As well, pushing the A/C button and turning the key on etc. should result in the fan coming on....A/C off and it should stop after a few moments.

And there is the direct test where you pull the connector at the fan, determine which wires are which, and then hot wire long enough to test. Don't energize the low and high circuits at the same time.

Thank you. One dumb question, if my air conditioning does not work (compressor does not kick on) will that effect testing to see if the high speed fan comes on when the ac switch is turned on.

thanks
 
Not sure, but my guess is it shouldn't matter. Punch the defrost button instead...

In that case, tho, just pull the ECT connector to start. If the fan runs then, you're basically ok. If not, then further testing may be in order.
 
And there is the direct test where you pull the connector at the fan, determine which wires are which, and then hot wire long enough to test. Don't energize the low and high circuits at the same time.

I just use an OHM meter across the pig tail connections on the fan side. Negative on the center wire and positive on each end. If the readings are not the same the motor is either bad or ready to go.
 
I just use an OHM meter across the pig tail connections on the fan side. Negative on the center wire and positive on each end. If the readings are not the same the motor is either bad or ready to go.

Good idea, and a great way to test a fan in a junk yard before committing to removal/purchase, etc.

I like hearing them run both speeds and being sure they're not rumbling/already worn out.
 
I like hearing them run both speeds and being sure they're not rumbling/already worn out.

I had a problem back in 2005 with my 95 Cougar. The fan ran at both speeds but the car stalled from time to time at idle. I used carCode OBDII software to monitor the fan operation. They came on at the set temperature. Finally, I discovered the source of the stalling using the OHM test.
 
I had a problem back in 2005 with my 95 Cougar. The fan ran at both speeds but the car stalled from time to time at idle. I used carCode OBDII software to monitor the fan operation. They came on at the set temperature. Finally, I discovered the source of the stalling using the OHM test.

Good work - sounds like you caught it right before it failed completely. Interesting the fan could stall the car....must have been quite the load on the electrical system.
 
OK, so the fan motor does work. What is the module that controls the fan that often goes bad. What is the actual part name. Fan Control Module??? Cant find it on rock auto?

thanks
 
OK, so I replaced the IRCM. The fan comes on only when the A/C is turned on. I am guessing the temperature sending unit that activates the fan is shot. Where is it located and is this the correct one?

http://www.rockauto.com/catalog/moreinfo.php?pk=951148&cc=1430181

or

MOTORCRAFT Part # DY1145 {#DY681, F2AF12A648AA, F2AZ12A648A} For vehicle with rectangular connector, includes pigtail for splicing if vehicle has round connector
E4AF-12A648-AA

thanks guys!
 
You ARE aware that there's a good chance the motor just isn't hot enough to kick the fan on without the A/C running, right?

This is where it's nice to be able to ask the ECU "Hey, bubba, how hot'za you is?" with something like a QuarterHorse.

RwP
 
You ARE aware that there's a good chance the motor just isn't hot enough to kick the fan on without the A/C running, right?

This is where it's nice to be able to ask the ECU "Hey, bubba, how hot'za you is?" with something like a QuarterHorse.

RwP

Its definitely getting too hot. Gauge climbs rapidly when stopped. When I turn on the A/C and the fan kicks on it immediately starts to go down. The fan is just not getting the signal to kick on. I changed my thermostat when I did my tune up with a 195 degree unit. Also put in a completely new radiator and all new coolant hoses and water pump.
 
Its definitely getting too hot. Gauge climbs rapidly when stopped. When I turn on the A/C and the fan kicks on it immediately starts to go down. The fan is just not getting the signal to kick on. I changed my thermostat when I did my tune up with a 195 degree unit. Also put in a completely new radiator and all new coolant hoses and water pump.

I had a similar problem. It wound up being a combination of the radiator cap, and coolant temp sensor by the passenger valve covers while it was at it I replaced the coolant sender for the gauge on the dash. Now it runs cooler and didn't cost that much $, plus the sensors are lifetime warranty. Fan now works like it's supposed to. Before that it wouldn't kick on at all. I did all of the above tests which lead me to the coolant sensor.
 
I had a similar problem. It wound up being a combination of the radiator cap, and coolant temp sensor by the passenger valve covers while it was at it I replaced the coolant sender for the gauge on the dash. Now it runs cooler and didn't cost that much $, plus the sensors are lifetime warranty. Fan now works like it's supposed to. Before that it wouldn't kick on at all. I did all of the above tests which lead me to the coolant sensor.

Thanks, I will change that next. I am guessing its the one with the electrical plug in connector. The parts places keep showing my the temperature sending unit that I already replaced which just goes to the temp gauge. Rock auto doesnt differentiate between them... They just show different photos.
 
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