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X3 Cooling Fan not working

61095 Views 34 Replies 7 Participants Last post by  16valex
Hi, I just had my aircon serviced and the mechanic told me that the aircon is fine, but that the radiator cooling fan is not working, thus preventing the aircon working properly as it controls the cooling fan. According to the mechanic there's power to the motor, but it doesn't run.

In addition to the aircon switch, I guess the cooling fan is controlled by a thermal switch or relay somewhere on the car, but as you can't get wiring diagrams I am at a loss as how to locate the control components and troubleshoot the problem. Has anyone had this problem and could suggest a troubleshooting procedure?
I want to check the control circuit out before resorting to replacing the fan assembly which is almost £550 from BMW in the UK!
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fan image files

dig in these images .....they have all the usual culprit bad bmws fan switches and some of the elec schematics.....let us know your exact model wishes

the classic fan switch test older bmw but still a good generic
some basic e83 elec one lines

see the 2 attachments for an overview of the fan and a basic elec drawing


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Dear SwampX3,
Many thanks for your quick reply and for the circuit deiagram.!
Do I understand correctly from this that the DME control module gives a variable output according to speed and temperature? This would mean that the fan is controlled electronically rather than through a relay, so If I have 12 volts at the main supply cable, and the speed of the fan is controlled by the pulse wave, there is no relay in circuit, then the most likely cause of the problem is the fan motor itself.

I ran the engine on my driveway this afternoon for about 15 minutes to get it hot and put the A?C on. Althouugh the temperature gauge was reading slightly over normal (gauge needle slightly to the right of vertical) after 15 minutes the over pressure valve blew off steam but the fan did not cut in. I switched off at that point. I have no leaks on the system and water levels are ok.

My X3 is a 2.0 liter diesel xdrive M-sport, which is a UK car
good sherlock homes work !

later bmws are as you described.....looks like you fall into this category....The electric fan is activated by means of a power output stage directly on the fan motor.....also ......check your power circuit fuse.....I will attach a maybe its your fuse link momentarily....also .....see the other good post I will attach soon

also ......the fan is very very easy to remove ....and very easy to test in situ.....just a good 12v power and ground to see whats what

also ....did you do the jump wire test at the temp sensor plug ????

location of the temp switch in the hose botton .....item no 23
post 4 covers the no relay / dme driven system

from the fest no 4 is the best

I thought you might be interested in reading this web page:

power fuse

I think X10016 might be the power fuse on yours .....just check on this link below

the fuse box location on your X will probably be on the opposite side cause of the English steering wheel location


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the old and new fan systems

this is the old fan test routine .....not yours though .....just academic

this is good way of testing the later system on the fan logic/power etc if you only have a meter that reads frequency etc and not a scope type meter.....also some good tips on the testing of the fan at the fan can disregard he has two fans and simply follow the logic on testing the one with computer logic for the number one below

I'm posting this because I searched every thread I could find on the subject of trying to figure out which component is the problem when your electric fan isn't working and there seemed to be a lack of information or what information was there was not correct.

I discovered my electric fan was not working on my 2000 328i (Manual). I wanted to test which part of the system wasn't working before I dropped $300 on a new fan. Here is what I found:

One main thing to point out is the Manual version of the car has a single electric fan on the engine side of the radiator. The automatic has an electric fan on the grill side of the radiator plus a mechanic belt driven fan on the front of the motor. The one on the grill side should be nearly identical in troubleshooting to the electric fan on the manual.

The fan is controlled by the computer (DME). The plug that goes into it has 3 wires (this is the plug on the left side when standing in front of the car facing the fan, the device mounted to the top of the fan is an air particle sensor and has no bearing on the cooling system). The two large wires are for power and ground, they are always live even when the car is off. They are hooked to the 50 AMP fuse in the glove box #36. The third wire is to control the fan speed and comes directly from the DME, there is no other fuse or relay in between. This wire carries a Pulse Width Modulation (PWM) signal.

The wires from this connector run to a box on the engine side of the fan (which the manual calls an "output final stage") and two wires go from there to the fan motor.

The car is supposed to run the fan for 20 seconds when you first turn the car on, then check to see if it is spinning, if the fan is not spinning the computer should set a code. I had no codes set on mine though.

The fan is almost always on at some speed if you have the A/C on, so perform tests with the A/C running.

The inputs the computer uses to decide how fast to spin the fan are:
Radiator outlet temperature
Catalyst temperature (calculated
Vehicle speed
Battery voltage
A/C pressure (calculated pressure)

To troubleshoot:
check computer for any set codes
unplug the fan connector and test for voltage on the two large wires.
If there is no power check the fuse in the glove box
If you have an oscilloscope you can use that to easily determine if you have a PWM signal on the wire from the DME, if not continue reading
Measure voltage from PWM wire to ground
I assumed my multimeter would give me the average voltage from a PWM signal but apparently not. I measured about .03 volts almost always when the car and A/C were on. I'll let the electronics buffs tell me why my assumption was incorrect.
If your multimeter has a frequency option test the frequency on the PWM wire.
On mine I measured 190hz during the first 20 seconds and 240hz after that. Many posts have said the correct range is 10-100hz, but unless my multimeter is very far off that is not the case
If readings on all those are ok then it's either the output final stage or the fan motor itself. You can check the motor by pulling out the fan and applying 12V directly to the motor (there is a small square plastic cap in the middle of the fan you can pop off for easy access).

In my case the motor would spin when powered so I figured it had to be the "output final stage". Unfortunately they don't sell just that part, you have to buy the whole fan, final stage, and shroud as a unit. (P/N 17117561757)

Note: I should point out that since my car was not setting codes when the fan didn't work I can't guarantee the computer will continue sending a PWM signal after the initial 20 seconds.
Last edited by devlspawn; 07-02-2012 at 04:15 AM.
devlspawn is offline
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supercourse post 3 nails it best

I thought you might be interested in reading this web page:

We don't have a step-by-step guide to checking the rad. fan so maybe it's time to try and compile one.

I'll start by offering a few notes or observations.

The electrical connector to the fan is 3-wire: (1) 12V always live, (2) ground and (3) signal from DME

You need something more than a basic multimeter to diagnose the signal wire.

If the live power is zero then it's likely that the fan motor bearing is dry or worn and the fan was drawing too much power and the protecting fuse (#37?) blew.

Or the blades are crudded up.

If 12V power looks good, then the problem has to be with the signal sent from the DME or signal received at the fan and its built-in switch/controller.

It's unlikely to be something simple like the $30 coolant temp. sensor (in lower rad. hose?) needing replacement.

If it was that, the fan should still spin briefly on initial start-up (when the control cycle re-initializes) and when A/C is activated.

From most reports on this forum, the problem is probably the switch/controller in the fan assembly.

Unfortunately not available as a separate replaceable part.

There are a few different fan assembly part nos. - probably based on A/T or M/T, maybe engine type, maybe manual AC or auto. climate control, and maybe model year.

You have to be careful to get the right one based on your V.I.N.

If you get an ebay one, the risk of being shipped the wrong one or a D.O.A. is likely a bit higher than from the dealer or a trusted online or local parts house.

So, first trouble-shooting step should be to watch the fan on engine start-up.

If it doesn't spin, a code should have been recorded. But you need a scan tool that reads Body and Chassis modules - not the popular emissions-only OBDII reader as at Autozone, etc.

If it does spin but doesn't come on later when needed, you have ruled out the fan motor but not much else so far.

Keep in mind that the coolant temp. sensor is only one of several triggers for the fan to come on, and that there are several fan speeds depending on the need.

WARNING: If temp. gauge is reading just past its usual mid-way point, be very careful. The next step to red hot can happen very quickly. The fan is essential when idling or crawling in traffic.
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wire color codes/e83 manual etc

helpful wire color codes and link to the e83 manual you will be very happy with if you has loads of elec drawings etc

they go for ~ 85 bucks here


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electric fan removal on e83 x's etc

the front end of this one shows the 5 mins to remove your electric fan
X3 Cooling Fan not working

Hi Swampx,
I decided to have a look at the fan assembly. As you say, it is very simple to remove it after taking off the airfilter housing and inlet duct complete with Mass Air Flow. 2 screws to remove, it unplugs and it just lifted straight off.
I tested the supply voltage with my multimeter and there was 12 volts at the supply side of the plug from the battery.

I removed the fan assembly and put 12 volts across motor side of the powercable, but the motor did not run, so I suspect it is the motor

There is another sensor mounted on the top right of the fan assembly(looking from the front of the car), which the chap at the BMW shop said was the aircon sensor. ( it loked like a small microphone with a mesh coverI cleaned this with brake cleaner but wasn't able to test any further. Not sure but I think this sensor links through the aircon switch.
I must buy myself a Bentlu manual as you recommend!

I have taken the precaution of ordering a raplacement fan from one of the BMW dealers in the UK who run an online shop and were able to give me a 20% on-line discount. It comes with a 2 yearwarranty direct from Germany, and If I can find some other reason whythe fan isn't working then I can return it and get a refund within 14 days.
I'll have a look at other posts and your troubleshooting guide and see what I can do.
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good sleuthing !

let's hope the new fan fixes the problem .....don't forget to log on to BMW and get your owners manual ....

below is the generic from the climate section of the manual for what probably is the little mesh polution sensor you cleaned up.....keep us posted on the fix wishes from the swamp @ 98F degrees today

the vehicle.
Press the button repeatedly to select
an operating mode:
***9655; LEDs off: outside air flows in continuously.
***9655; Left LED on, automatic recirculated-air control:
a sensor detects pollutants in the outside
air and controls the shutoff automatically.
***9655; Right LED on, recirculated-air mode: the
supply of outside air
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link for owners manuals

they gotta have one for european drive cars and check ....her is the n american link for the owners manual downloads pronto in pdf format,d.cGU
fixed the fan ????

did you manage to fix the fan ???
Cooling Fan not working

Dear SwampX3 and other contributors,

My apologies for the late reply, but a couple of days after my last post I had to go into Hospital for several days after being attacked by my Gall Bladder with the most excruciating pain! I am now recovering and waiting for a date to go in for the operation to remove it.

However, back to the cooling fan issue.

My new fan assembly arrived from a BMW dealer in Germany last week. 25% cheaper than I could buy it in the UK, but still an eye watering £477.00 ( around $700). Ouch! However it did come with a 2 year warranty and I can return it to any BMW dealer in Europe if it fails again.

Having loked at the video you posted and reading through the advice, I took out the filter housing and MAF ducting and removed the fan assembly inside of 10 minutes. I verified the power suply was ok, then installed the new fan in about 2 mins. Then I also tok the opportunity to change the air filter whilst the filter box and Mass Airflow Sensor Unit were out. Total time 25 minutes all in. (Mylocal BMW dealer thought they would need 2 to 3 hours)

After connecting every thing up. I switched on the ingnition, then switched on the aircon to AUTO. The fan began a soift start and ran up to full speed then I started the engine and left it running. Within 15 seconds the aircon was pushing out ice cold air!

Over the past few days of driving the car, it looks like the issue has been completely resolved. Without aircon working and in flowing traffic, the fan doesn't need to run, but as soon as the aircon is turned on to Auto the fan starts. If I get in standing traffic it will also kick in, so I am confident tha matter has now been resolved.

Now, Has anyone ever had one of these fan units apart to get at the internal components?? With the price of these cooling fan assemblies it must be worth trying to identify which electronic component has failed and replace it!

Thanks again to all who contributed and helped me!
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great news

very good resolution.....also hope you can delve into the electronics and find a card /circuit fixer with the magic needed's a bit like the electric water pumps on many vehicles .....something goes wrong on the electronics and it's a dig in the wallet and the mechanical side is of health to you and many more years on this Fest and DIY ing

PS ......come visit the swamp ......the fans never take a break in the heat and humidity !
the aircon also dehumidifies

maybe wanna leave the aircon on cause it dehumidifies the incoming air before it's heated .....this helps mucho when its damp it helps keep the windows clearer and inside cabin drier
the front end of this one shows the 5 mins to remove your electric fan
Well I watched a few videos on replacing electric fan. Problem is my air dam (?) is not the same as the ones in the videos. No little plastic clips, etc. So I have not been able to get it out to get to the fan. see pic
Land vehicle Vehicle Car Hood Grille

What to do-what to do??
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