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Why cheap Fan Control Modules don't work (2004+ models)......
After advising lots of people on why the cheap modules (one guy put 3 cheap ones in before using an OEM yhat fixed problem) don't work and looking like I am now in the market for replacement =
Let's begin with the basis =
The control system for the fans is a bit complex! Easiest explanation is to quote JTIS:
Two variable speed electric cooling fans are housed in the cooling fan shroud for the cooling of the radiator. The speed of the electric cooling fans is adjusted by the cooling fan control module, which is controlled by the engine control module (ECM).The ECM determines the cooling fan speed by receiving inputs from the cylinder head temperature (CHT) sensor. The ECM sends a variable pulse width modulated (PWM) signal to the cooling fan control module to operate the cooling fans at the required speed. The cooling fans are operated at slow speed when the engine coolant temperature is at 95°C (203°F) and are operated at full speed when the engine coolant temperature is at 105°C (221°F). A coolant temperature between these temperatures will cause the cooling fans to be operated at a speed which is proportional to the engine coolant temperature.When the engine is running with the CHT above 100°C (212°F), if the ignition switch is turned to the OFF position the cooling fans will continue to operate for a time which is determined by the ECM. If the PWM signal from the ECM to the cooling fan control module is between 7% and 95% the cooling fan control module will operate the cooling fans at the required speed. If the PWM signal from the ECM to the cooling fan control module is below 3% and above 95% the cooling fan control module will operate the cooling fans at maximum speed. If the PWM signal from the ECM to the cooling fan control module is between 3% and 7% the cooling fans will not operate.
Okay, now for my supposition in the research I have done. In looking at dozens of pictures from cheap knock offs (the original is a Gates FCM134), it appears that on the plug (the main one on the driver's side) the original has 4 wires as does the receptacle (4 pins). On the cheap knock offs, the receptacle has 3 input receptors, thus why they don't work correctly as they are not receiving all the input(s) they require. Another problem seems to be that :
1. The China product does not include two inductors and several capacitors found in OE equivalent. This results in substantial electro-magnetic emissions from the China part which could interfere with or damage other vehicle electronics.
2. The China product will not run at 100% duty cycle, exactly when the vehicle is demanding full fan speed! The product lacks two inductors which protect the module from overheating, even at 100% duty cycle. The China part simply shuts off to avoid overheating and can burn out when 100% duty cycle is commanded, resulting in no fan operation when the vehicle needs it most!
3. The original module is designed to operate two fans, each commanded via a separate channel in the module. The China product has only a single channel of operation and therefore is incapable of operating the two fans separately.
4. The China product lacks an important redundant capability found on oe module. If one fan fails, the oe module automatically speeds up the other fan to continue cooling. The China product does not have this feature.
I have found an after market product sold in the United States (CA) for a pretty good price. And way cheaper than C2S49717 that Jag wants you to buy.=
So member Dr. Dome to the rescue once again. Sending me one from a 2006 wagon he's parting out. Thanks Dr.!! Fingers crossed that this is the fix. He believes the high side part of the FCM has failed.
hello dell,
I remember you getting one of these opened up ? or wanting to, i may be mistaken.
I would appreciate the way it was opened, i tried opening mine with a drill, i drilled too close and got into the mail board, not to mention not being able to separate the top from the bottom
there was another post with pictures but they are long gone.
Good post, but today in a pickle! Called Moss where part is 8 weeks b/ordered. Any suggestions? Otherwise I'll have to get clipped purchasing entire unwanted unit.
1. The China product does not include two inductors and several capacitors found in OE equivalent. This results in substantial electro-magnetic emissions from the China part which could interfere with or damage other vehicle electronics.
Your results are assumptions.
Originally Posted by Dell Gailey
2. The China product will not run at 100% duty cycle, exactly when the vehicle is demanding full fan speed! The product lacks two inductors which protect the module from overheating, even at 100% duty cycle. The China part simply shuts off to avoid overheating and can burn out when 100% duty cycle is commanded, resulting in no fan operation when the vehicle needs it most!
Two of my China CFMs runs at 100% duty cycle (unfortunately all the time at ignition-on).
The overheating matter is unproven. The owner of my X-Type said they're running at full speed for about 1.5 years.
Originally Posted by Dell Gailey
3. The original module is designed to operate two fans, each commanded via a separate channel in the module. The China product has only a single channel of operation and therefore is incapable of operating the two fans separately.
Unproven!
There's only one control wire (PWM signal). Both fans are controlled together - should have the same speed!
Originally Posted by Dell Gailey
4. The China product lacks an important redundant capability found on oe module. If one fan fails, the oe module automatically speeds up the other fan to continue cooling. The China product does not have this feature.
I don't know: first the connector of one of my fans had an loose contact, one fan didn't run, the other one ran at full speed - but now both are at full speed due to a further failure (I don't found the root cause yet) so at the moment I cannot check these protecting feature.
Originally Posted by Dell Gailey
I have found an after market product sold in the United States (CA) for a pretty good price. And way cheaper than C2S49717 that Jag wants you to buy.=
I think the $25 China modules are operatable, too
Originally Posted by Dell Gailey
This is the "4 pin" receptacle I spoke of. Notice how the Asian ones are 3 pin lacking the top connection
The pin / wire 4 get's 12V from the EMS relay when ignition-on (perhaps power distribution for inner controller section of the CFM). It seems to be not really important. The 3-pin-modules are capable to switch on as soon as control wire works against ground (PWM signal), the ignition-on wire isn't nessecary.
But I'm still looking for my failure. The radiator fans are running at full speed as soon as ignition-on (A/C is off). The PWM signal is all the time about 93% high and 7% low.
#1 = not an assumption, the Asian lacks the inductors and capacitors.
#2 = OEM runs each fan separately at speeds called for by sensors. So there are variable speeds according to car needs. Asian does (as you state) run both at 100% ALL THE TIME @ IGNITION even when it's not needed and based on reports here on this forum and elsewhere they tend to burn out. That is IF THEY WORK AT ALL.
#3 = not unproven just factual based on interior electronic components.
#4 = OEM 4 pin female, Asian 3 pin female. Again just a fact. My conclusion is this 4th contact is essential in the OEM using input from sensors and PWM to vary 1 or 2 fan(s) running (independent from each other) & the speed of each fan. Additionally the OEM has the ability to increase one fan speed exponentially upon need in case of the failure of 1 of the fans. Asian simply CANNOT do this, it doesn't have the interior electronic components.
The OEM also has the electronic components to allow the fan or fans (@ variable speeds) to run after engine shut down for a period of time to cool down the car if called for by sensors and then automatically shut off when cooled down parameters are met.
I've visually seen 1 fan running, changing speeds, then 2 fans running at different speeds and finally both fans running at full speed each.
Thus when mine (FCM) failed and seemingly the most common seen by others, my fans ran continuously with ignition off never stopping. Like the car needed cooling down. For lack of a better description the "high side" portion of my FCM failed. The car thought it was overheated and needed cooling down
JUST FACTS
Last edited by Dell Gailey; 05-14-2021 at 05:04 PM.
I've prepared a document for upload with descriptions (wiring diagrams, photos, etc.) but not finished yet.
Originally Posted by Dell Gailey
#4 = OEM 4 pin female, Asian 3 pin female. Again just a fact. My conclusion is this 4th contact is essential in the OEM using input from sensors and PWM to vary 1 or 2 fan(s) running (independent from each other) & the speed of each fan. Additionally the OEM has the ability to increase one fan speed exponentially upon need in case of the failure of 1 of the fans. Asian simply CANNOT do this, it doesn't have the interior electronic components.
The OEM also has the electronic components to allow the fan or fans (@ variable speeds) to run after engine shut down for a period of time to cool down the car if called for by sensors and then automatically shut off when cooled down parameters are met.
I've visually seen 1 fan running, changing speeds, then 2 fans running at different speeds and finally both fans running at full speed each.
The 4th pin is switched to 12V from EMS relay during ignition-on (nearly - I didn't investigate EMS relay function in deep, but it distributes power to several fuses / systems).
So the CFM has only one control wire / one control signal for the demanded ventilation. So the car / the ECU can only demand one ventilation level at the same time.
Of course, the CFM itself could control the two fans differently dependent on the demand signal. I don't know.
Perhaps your observation could be a result of a loose contact of one fan, too (I fell for it in the beginning). But you could be right, too, of course.
Cheers, catfondler
Last edited by catfondler; 05-14-2021 at 05:39 PM.
#2 = OEM runs each fan separately at speeds called for by sensors. So there are variable speeds according to car needs. Asian does (as you state) run both at 100% ALL THE TIME @ IGNITION even when it's not needed and based on reports here on this forum and elsewhere they tend to burn out. That is IF THEY WORK AT ALL.
Unfortunately I don't own a PWM simulator, so i'm not able to do a quick check for the variable speed function of my both China CFMs.
But for simple on/off function there are to many integrated components on the PCB.
My both CFMs switch on a few seconds after ignition on, and switch off from about 3-7 seconds (in different situations) after ignition-off.
Consequently I assume the ECM controls this delays. (Could be perhaps a inner function of the CFM, too.)
My newest observation:
If I switch the A/C on, the fans turns a little lower for about 25-30 seconds. Seems to be the PWM speed control is running basically on the China CFM.
(I didn't investigate that with oscilloscope until yet.)
Cheers, catfondler
Last edited by catfondler; 05-14-2021 at 07:01 PM.
Looking at his country explained a lot to me. Unfortunately, I'm that on great grandmothers side as well. The ECM is not the only sensor that inputs for the fans, just one of the others is the CTS.
The sensor works by measuring the temperature that's being given off by the thermostat and/or the coolant itself. The temperature is then sent to the on-board control system. ... As the control system receives the temperature from the CTS, it may trigger the cooling fan to either shut off or turn on.
Last edited by Dell Gailey; 05-14-2021 at 07:34 PM.
Dell, please explain "ECM sensor" and "CTS" (Coolant Temperature Sensor? Jaguar calls it "ECT sensor".)
(ECM sounds like Engine Control Module, I used ECU[nit].)
I know that ACCM/CCM (i.e. with A/C pressure sensor) is involved in fan speed control, too. Perhaps transmission fluid temperature sensor (FTS).
(Unfortunately my new thread on fan speed problem isn't released by an administrator until now. There is some additional info.)
Can you tell me what my country of residence explains to you?
(I'm honestly interested in learning about prejudices.)
Cheers, catfondler
Last edited by catfondler; 05-14-2021 at 08:00 PM.
The acronyms are somewhat region specific. ECU/ECM = same thing. CTS/ ECT (also called ECTS) = Same thing MIL/EML = Same thing.
Just semantics.
Or British Boot/Trunk, Bonnet/Hood etc. Nearside and offside always confuses me, lol.
I'll do one more shot then leave it to future readers to decide which makes sense to them.
The ECM (Engine Control Module) receives various sensor signals (Engine Temp, AC on or off etc.)
The ECM requests the desired fan speed. The ECM has 2 control signal lines going to the Fan Control Relay Module. The Fan Control Relay Module contains internal relays.
Possible Combinations of the 2 Signal Lines:
1) The ECM does not energize either control signal line = Both Fans Off.
2) The ECM energizes the Low Speed Signal LineOnly on ONE FAN = One Fan is connected and receives V. One fan running.
3) The ECM energizes the Low Speed Signal LineOnly on BOTH FANS = Both fans are connected to V and run on low.
4) The ECM energizes the High Speed Signal Line Only on ONE FAN = Fan is connected and receives V. One fan is on high.
5) The ECM energizes BOTH, the High Speed Signal LineAND the Low Speed Signal Line. Each fan is receiving V but at different calls for speed. One fan on high, one fan on low.
6) The ECM energizes the High Speed Signal Line Onlyon BOTH FANS = Both Fans are connected and each receives V. Both fans are on high.
Bear in mind high and low speed are subjective terms used as the PWM (pulse width modulation) signals comes into play in the revolution speed of the fans (think dimmer light switch).
Last edited by Dell Gailey; 05-14-2021 at 09:01 PM.
Yes, and I've to understand your acronyms in detail to understand what did you meant.
"The ECM is not the only sensor" is difficult to understand (because ECM/ECU isn't a sensor).
And what about your German great grandmother? What do you think about Germans?
Ah, you've edited / completed your previous post. Unfortunately you're wrong again. Maybe you mixed up the car or model.
There are no two control signal lines! The second line "77 E" (the missing 4th pin) is a power distribution line ("WG" = white / green).
You'll see it at the wiring scheme from "2005 MY X-TYPE Electrical Guide.pdf".
See symbol "B+": it's battery voltage (via EMS relay: power for Engine Management System).
And only one "I"nput line, see triangle symbol including an "I". ("O" are outputs. "P" is ground. "B+" is battery voltage.)
CFM (newer version)
What a shame, I hoped that you had a deeper knowledge about the cooling system at these X-Type cars (with Ford [Mazda/Suzuki] motors) - because of your convinced opening post - so we can solve my problem (another thread) together.
Now I've to fight about basics...
In addition, the CFMs doesn't include "relays". More kind of "semiconductor relays". (Difference is important because of fan motor speed regulation is not of slow switching on and off, it's because of fast modulating the fan motor's power.)
Edit: And the ECM don't energize the PWM line, it switched this line to ground in pulses. (And this switching to ground is also the signal for the CFM to start to operate. If the line is "open" on ECM side, the CFM is off.)
And by the way, again: Why are you sad about your German ancestors? (Germany: the country of the inventors of Otto and Diesel engines.)
Cheers, catfondler
Last edited by catfondler; 05-15-2021 at 08:31 AM.
08-30-2019, 11:34 PM
Why cheap Fan Control Modules don't work (2004+ models)......
