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Hello,
the problem is that the cooling fan spins very slow regardless of AC or car temperature.
The car in question is S-type 3.0, 2003 model.
Even with the AC running at "Low" the fan spins super slow.
When the car reaches 95°c the fan starts spinning the same slow speed as if the AC is on.
Even when the car reaches 105+°c the fan wont speed up.
I have videos that I will attach so you can get an Idea.
And just to point out somethings:
The thermostat is stuck open.
The ECT sensor is working right.
There is no Fault codes about the fan or cooling in general.
At 111c it was the same speed with no change.
And when I say it's slow I mean it. It basically doesn't do anything. Can't feel any airflow.
Does someone know where is this controller for the fan? Cause it's not on the fan shroud.
You say it's a 2003 car - do you mean MY2003 & which market?
I expect the location is in one or more of JTIS, parts stuff & Electrical Guide, based on the above details.
I'm not sure what you mean by MY2003.
It was originally imported from Italy if I recall correctly.
The VIN of the car is SAJAA01P74FN02165 I guess this will give more info about the car than I can.
Does that have any significance?
Its the facelift and from what I have gathered the control module is integrated in the fan motor. But I have yet to confirm that myself.
At 111c it was the same speed with no change.
And when I say it's slow I mean it. It basically doesn't do anything. Can't feel any airflow.
Does someone know where is this controller for the fan? Cause it's not on the fan shroud.
Is the fan spinning at all? This isn't quite clear from your description.
2003+ radiator fans have a different motor than the early models. From what I understand, the later style is brushless and should last a long time. (The early style has regular carbon brushes that eventually wear out.)
I do not know if the later style has a separate control module. Per the wiring diagrams, it does. You can see your wiring diagram here at the top of the page, then navigate to figure 03.2 for the V6 engine:
Page 49 says the controller is integral to the motor. So I'm thoroughly confused. Best you can do is follow the wire harness from the motor and see where it leads.
Whether the controller is integral or separate may be a moot point, so be careful not to get too sidetracked. Back to the question of whether the fan is even spinning. If not, check these two fuses in the front power distribution box under the hood:
F38 - 10 amp
F13 - 80 amp - This will be a large cartridge style
If the fan is spinning, you can test airflow by placing a rag across the grill. Run the engine and switch on the AC to make sure the fan is commanded to run. Here's a pretty picture showing the results on my '02:
If the fan is drawing an adequate volume through the radiator, the rag will be held tightly in place. Don't run the engine for more than a few minutes like that as cooling airflow will be restricted, but it's fine for a quick test.
If the fan is indeed running, what symptoms are you seeing? Is the temperature gauge climbing above the center mark? Please be aware the temperature gauge is deliberately misleading. A temperature range of approximately 80-110C is considered normal, and the needle will be centered. The temperature has to climb above 110C before the needle moves above center. I noticed your scanner display has arbitrarily put a red band starting at 105C, but per Jaguar's logic, that is still within the normal range, although near the top. Your car may be perfectly happy with 105C coolant but your scanner is scaring you. I'm not sure when the fan is commanded to run at high speed, but your car may not be at that point.
Is the fan spinning at all? This isn't quite clear from your description.
2003+ radiator fans have a different motor than the early models. From what I understand, the later style is brushless and should last a long time. (The early style has regular carbon brushes that eventually wear out.)
I do not know if the later style has a separate control module. Per the wiring diagrams, it does. You can see your wiring diagram here at the top of the page, then navigate to figure 03.2 for the V6 engine:
Page 49 says the controller is integral to the motor. So I'm thoroughly confused. Best you can do is follow the wire harness from the motor and see where it leads.
Whether the controller is integral or separate may be a moot point, so be careful not to get too sidetracked. Back to the question of whether the fan is even spinning. If not, check these two fuses in the front power distribution box under the hood:
F38 - 10 amp
F13 - 80 amp - This will be a large cartridge style
If the fan is spinning, you can test airflow by placing a rag across the grill. Run the engine and switch on the AC to make sure the fan is commanded to run. Here's a pretty picture showing the results on my '02:
If the fan is drawing an adequate volume through the radiator, the rag will be held tightly in place. Don't run the engine for more than a few minutes like that as cooling airflow will be restricted, but it's fine for a quick test.
If the fan is indeed running, what symptoms are you seeing? Is the temperature gauge climbing above the center mark? Please be aware the temperature gauge is deliberately misleading. A temperature range of approximately 80-110C is considered normal, and the needle will be centered. The temperature has to climb above 110C before the needle moves above center. I noticed your scanner display has arbitrarily put a red band starting at 105C, but per Jaguar's logic, that is still within the normal range, although near the top. Your car may be perfectly happy with 105C coolant but your scanner is scaring you. I'm not sure when the fan is commanded to run at high speed, but your car may not be at that point.
Soo today I disassembled the fan from the car.
The module is build in the motor. (Picture below)
The fan was spinning very slow (you can see in the video in the first post).
Yesterday I tried when the A/C is on and it was spinning at slow speed.
At 95°c it started to spin again with the same slow speed.
At 105°c the speed didnt change. At this point it should be at max speed.
At 111°c it didnt change the speed of the fan.
Today I tried it with the A/C again and it didn't spin at all.
So basically no airflow whatsoever even when it spins cause its super slow.
When I give the fan some power to the main wires with another battery it does NOT spin.
I dont know how the module work and how can I test it.
Is there any way that I can make the fan run at full speed when the ECT is at 95°c? It will be enough for me this way.
Soo today I disassembled the fan from the car.
The module is build in the motor...
Okay, making some progress.
I would not try to hotwire the motor or otherwise bypass the control module. The cheapest, quickest option may be to find a useable spare on eBay or other online sources such as Car-Part.com.
It strikes me as odd to locate the module in such a hostile environment, due to the heat and vibration. When old electronics fail, one common fault is a capacitor failing internally and swelling. Here's a good primer showing how to visually inspect them:
If you find any failed capacitors, it's usually fairly easy to replace them if you are handy with a soldering iron.
Next, use a magnifying glass and carefully inspect all of the solder connections on the circuit board. Look for any dull or grainy solder. If so, that indicates a cold solder joint which is prone to cracking. A good solder joint should have a smooth and shiny appearance. Take a look at this thread, showing how a bad factory solder joint caused a flickering odometer display:
I would not try to hotwire the motor or otherwise bypass the control module. The cheapest, quickest option may be to find a useable spare on eBay or other online sources such as Car-Part.com.
It strikes me as odd to locate the module in such a hostile environment, due to the heat and vibration. When old electronics fail, one common fault is a capacitor failing internally and swelling. Here's a good primer showing how to visually inspect them:
If you find any failed capacitors, it's usually fairly easy to replace them if you are handy with a soldering iron.
Next, use a magnifying glass and carefully inspect all of the solder connections on the circuit board. Look for any dull or grainy solder. If so, that indicates a cold solder joint which is prone to cracking. A good solder joint should have a smooth and shiny appearance. Take a look at this thread, showing how a bad factory solder joint caused a flickering odometer display:
Considering the vibration present at the circuit board, a failed solder joint is a strong possibility.
No visible problems with solder or capacitors. Already checked them.
I think that the motor is fine but the module is the problem. Any known way to bypass the module? I will modify my fan if there is a way. As I said if I can make it spin at max when the coolant temp is as 95°c it will be great.
Are you sure it's the module rather than the fan motor(s)? (Or connection between them?)
Judging by the few posts this is an uncommon issue.
Well the motor is brushless so there is little to fail.
And yesterday it was spinning by its on power . It was slow but the fan was spinning.
The fan spins easy by hand with no wobble or whine.
The only grey area is the module and how it works
The only grey area is the module and how it works...
Did a little more digging. You have a brushless DC motor. It will not run by simply connecting DC power to it. It requires electronic wizardry to convert smooth DC power into the AC pulses needed to drive the motor, control the speed, and even the direction of rotation.
Here's a nice primer on the subject. Be sure to read part two, linked at the bottom of the page:
Did a little more digging. You have a brushless DC motor. It will not run by simply connecting DC power to it. It requires electronic wizardry to convert smooth DC power into the AC pulses needed to drive the motor, control the speed, and even the direction of rotation.
Here's a nice primer on the subject. Be sure to read part two, linked at the bottom of the page:
Just talked about that with a friend of mine.
He said the same thing. And that explains why the fan didn't spin when we tried with external battery directly.
That rules out the option of manual control or using thermal switch. Basically I need to by second hand fan and hope that it works. 🤷🏻♂️
Similar issue. Recently changed the heater hose now the fan spins at slow speed only once 90°c is reached. Never speeds up. Stumped might change the dccv next but could it have to do with the alternator? I see the voltage drops to about 11.7 after a couple hours of driving thats when the high temps start.
Similar issue. Recently changed the heater hose now the fan spins at slow speed only once 90°c is reached. Never speeds up. Stumped might change the dccv next but could it have to do with the alternator? I see the voltage drops to about 11.7 after a couple hours of driving thats when the high temps start.
11.7V is WAY too low. You should be seeing more like 13.7V. That definitely needs to be corrected. Is the low voltage responsible for the fan problem? Seems likely, but even if not, that isn't right and will eventually leave you stranded.
Is the alternator at fault? Most likely, but have the battery tested first. A bad battery can pull down the system voltage. It's kinda like trying to inflate a balloon with a hole in it, or filling a bathtub with the drain open.
If the alternator is bad, make sure the replacement is designed specifically for Jaguar. Some aftermarket replacements will charge just fine but don't communicate properly with the rest of the car. You end up with the little red battery symbol constantly illuminated.
Venko007, do you think low system voltage could be causing your fan controller to misbehave? Maybe it's even a normal load-shedding response to conserve battery power if the system voltage dropped too low. I don't know the Jaguar specifics, but many newer cars do have such a feature to reduce electrical loads in an emergency.
11.7V is WAY too low. You should be seeing more like 13.7V. That definitely needs to be corrected. Is the low voltage responsible for the fan problem? Seems likely, but even if not, that isn't right and will eventually leave you stranded.
Is the alternator at fault? Most likely, but have the battery tested first. A bad battery can pull down the system voltage. It's kinda like trying to inflate a balloon with a hole in it, or filling a bathtub with the drain open.
If the alternator is bad, make sure the replacement is designed specifically for Jaguar. Some aftermarket replacements will charge just fine but don't communicate properly with the rest of the car. You end up with the little red battery symbol constantly illuminated.
Venko007, do you think low system voltage could be causing your fan controller to misbehave? Maybe it's even a normal load-shedding response to conserve battery power if the system voltage dropped too low. I don't know the Jaguar specifics, but many newer cars do have such a feature to reduce electrical loads in an emergency.
Well if the voltage is low I think it will be logical to have a low battery warning or some kind of code in the PCM. I dont have such a thing. When I measured the voltage to the feed wire of the fan it was constant 12,5. The engine was not running cause of the parts that I removed. The signal wire going to the fan module was 12,5 and went down to 11,7 but that was after I turned on the A/C and again the engine was not running. So with the engine off its normal to see some voltage drop when I put the A/C on with the interior fan on full blast. It sounds strange that the car will choose to not run the fan with a hot engine and overheat cause of low voltage. And again no warning.
Update: Interesting thing is that we connected the fan to the car again and with the engine off and the key on (second position) with the A/C on the fan didnt spin as expected after all the engine is off. But when I turn the key off the fan spins for a moment 🤔 So the motor is ok and wires are ok cause they get electricity and signal to the fan. Today I will get the engine back together to the point that I can turned it on and try to see what results I will get with it on.
Well if the voltage is low I think it will be logical to have a low battery warning or some kind of code in the PCM…
Agreed. But didn’t your Mom ever teach you that what you wish for and what you actually get are often two separate things?
I’m not sure if our Jaguars ever give the driver a warning about low system voltage. This would be nice, but don’t remember anybody ever mentioning it here.
I haven't had any major problems with the charging system on my '02, but did on a Lincoln from the same era. Much of the internal logic seems to be very similar, sharing the same parent company. What I learned (the hard way, of course) is that the little red battery light is not as simple as it looks.
Years ago, on the cars with that idiot light, it was a very simple system. In nearly all cases, it could alert you to a problem, although often too late. The light compared alternator output to battery voltage, that's all. If the battery voltage was higher than the alternator output, that indicated a failure and the light would come on. For partial failures, with only a slight voltage difference, the light came on dimly and was easy to miss. That's how cars operated back when men were men, and women generally were not.
Throw all that knowledge out of the window. On our Jaguars, the light operates differently. In theory, the light stays off when the alternator's self-diagnostics say all is good. Light off = Alternator valid. Light on = not valid. Usually, I should add. If the alternator's control module suffers a total failure, it can't turn on the warning light. The battery will run down and you won't know until it's too late and other things start misbehaving. The alternator has to be at least partially alive or it can't warn you of a failure. It's a huge shortcoming. It's like how a sick person can tell you they're not feeling well, but not so from a dead person.
Oh, so the engineers were aware of this and at least provided a backup warning, right? Oh, stop it, that's funny. When my Lincoln's alternator quit, there was no warning light or other symptoms for a while. The battery was still powering everything adequately for a short time. Then the AC shut itself off. I tried to roll down a window, and they wouldn't work. Next the radio quit, and eventually the dashboard went nuts and shut down most of the display. I was only a short distance from home, so limped the rest of the way with the engine barely running. As I turned into my driveway, I got a Low Voltage alert on the remnants of the dash display, WAY too late to be of any value.
Now I'm not sure what sort of offical low voltage warning our Jags might give, if any. But in my case, I think some of the “failures” were actually load-shedding to get me safely off the road with the engine running off battery power. I just wish the system could have alerted me earlier.
Do our Jaguars have a similar feature? Don’t really know, but some of the behavior fits the pattern.
It’s easy enough to rule out. Put a voltmeter on the battery posts and start the engine. On a 2003+ car, you should see around 14.5V for the first couple of minutes, settling down to around 13.5V.
Running my v8 this weekend and notice when the volts are above 13 no overheating occurs. Wonder if half a volt is enough to cause the temps to rise. Starting to think its the head gasket but no coolant missing and it doesn't appear to be mixing. Gotta see if there's a pinched hose somewhere but in November I changed some hoses, entire fan, radiator, ect sensor and thermostat because of overheating. Maybe she won't make it to a quarter million miles after all. At 227000 miles now. Alternator dips into 12v and 11volt territory but now it won't climb past 97°c. So weird. Time to rebuild alternator and try a different thermostat
04-11-2024, 11:09 AM
Cooling fan won't run at full speed
