E39 Auxiliary Fan DIY write up-With Pics.

SleekBMW · May 13, 2007

MODS PLEASE STICKY

Thanks to E39Dream for helping me when i did it and being patient to answer my questions.
DISCLAIMER:

I am not responsible for any damages to your car upon using this or any other DIY write up. You assume all responsibility for damages or improper installation to your car.

Hello,

Here is a write up for a E39 Aux fan change. This was done on a 1999 528I and may differ slightly for your car.(resistors)

Job difficulty
2.5 wrenches out of 5.

Tools Needed
-1/4' ratchet
-3/8' ratchet
-8mm socket
-10mm socket
-13mm socket
-Needle nose pliers
-T45 torx bit
-8' extension

Parts Needed
- Auxiliary fan assembly - see No. 5 in link below
http://realoem.com/bmw/showparts.do?...& hg=64&fg=55
-Resistor No. 08 on link above.
- 50 amp fuse
- various fuses.
- Rivets Nos. 22 and 31 ten of each
http://www.realoem.com/bmw/showparts...& hg=51&fg=15
before ANYTHING.
Turn your ac on after your car has been operating for a while and is HOT
60 degrees and wait, if fan turns your aux fan is fine, if not you have a problem.

I have been told it can be your aux fan assembly itself, blow fuse, OR coolant temp sensor, or failed relay (ive been told this is very rare.)

FIRST THING, check the fuses in your glove compartment,
Fuses in glove compartment guide

This is a pic of fuse 75 and 76 lookin lying down above into your glove compartment from the passenger side foot well. That panel needs to be pulled BACK towards the passenger side seat with SLIGHT pressure to the floor and should come out. THE AREA THAT 75 and 76 are in is circled. you will reach in there, and grab the fuse and push UP towards the sky and it will come out.

Preparation

park your car on a flat leveled surface or your driveway.

put a blanket or sheet infront of your bumper, and set weights down so it doesnt fly away, i used my tool box.

here we go!

1-

Use the 8mm bolt to remove the 4 bolts that hold the headlight. Make sure you remove the bulbs from the housing of the headlamp.
there are 4 screws 2 on top and 2 on bottom.

2-

Remove 3 bolts from your wheel well, 1 above and 2 on bottom. refer below

Top bolt

Bottom bolt-the second one is just left to that, it may help to turn your tires side to side.

3-
Go and lie down on the sheet you just put in front of your front bumper.
You will look above the grills in your bumper and see little buttons, these are the plastic rivets. MAKE SURE YOU BUY EXTRA ONES FROM THE DEALER. 10 OF EACH TO BE ON THE SAFE SIDE IS WHAT I DID.
use the needle nose pliers and pull away the center pin, and pull out the rest of the rivet. there are about 4 rivets on each grill, pull them all out and pull away the grill.

4-

You will now see T45 torx bolt on the left of your license plate, and the right, the grill covered this area. Heres a pic
find both and unscrew using the T45 bit.

5-

Disconnect fog lights from the back
You should now be able to remove the bumper, MINE however was unremovable. so i had to remove the bumper shock absorber
pictured below
This isnt necessary to remove it, but if your having a tough time getting the bumper off, it helps.
after you have done 1-5.
have a friend support the bumper while you go to each side and SLIDE out the bumper from its track, it sits in a sliding track.

6-

This is what your car should look like now.

7-

Use a 10mm bolt and remove 3 bolts that hold this air snorkel.
the next one is to the right UNDER the snorkel.
last one is all the way to the right. cant miss it.

8-

Use the same method that you used for the grill on these plastic rivets
Remove ALL 3

9-

This rivet holds the power supply to the Fan, disconnect the wire this wire from the fan assembly
This is another rivet that i broke, but my dealer gave me a plastic zip tie and said this is better

10-

Remove 4 fan bolts, these are the 13mm bolts. there are 4. do the same on the opposite sides
also remove the kidney shroud which you removed the 3 rivets from. BE VERY DELICATE WITH THE SHROUD it breaks easily.

Front right

front right bottom

11-

Gently remove the fan frame assembly. MAKE SURE YOU SEE EVERY LITTLE POINT IN TAKING IT OFF, THE NEXT ONE NEEDS TO BE MOUNTED ON EXACTLY THE SAME OR IT WONT WORK.

Once removed, clean all the crap.
(if you have a resistor now is the time to replace it use diagram to locate resistor, if its not there you dont have one.
http://realoem.com/bmw/showparts.do?...& hg=64&fg=55 number 8)
Hook up the fan, let the car run for a bit and see if the aux fan is working, there is no guarantee it will work, because the engine needs to be at a certain temp.

Put everything back together again.

Go to Autozone, buy R134a with a guage, turn ac on at 60 and fill the AC to the BLUE level of the guage.

If after ALL of this your aux fan is not working, it could be the coolant temp sensor pictured below

Buy soda, drink, and look at the progress youve made. and now
Congratulations your Auxilary fan is now working. its better than paying 900 at the dealer right!

Cost
Aux fan assembly 297
50 amp fuse 2 dollars.
rivets about 3-5 dollars.
coolant temp sensor 22
resistors 60
soda 1.39

DISCLAIMER:

I am not responsible for any damages to your car upon using this or any other DIY write up. You assume all responsibility for damages or improper installation to your car.

QUESTIONS!?!?!

Pm me.

Hotswimmer · May 13, 2007

Beautifully done. Thanks for sharing this with us.

SleekBMW · May 13, 2007

Your welcome and ty

rcatank · May 13, 2007

how long did this fix take you?

SleekBMW · May 14, 2007

for a newb at this stuff, it will take you 3 hours, keep in mind i took the car apart 3 times, first time 3 hours(forgot parts)

then 45 mins after that.

XThang · Jun 18, 2007

Great Stuff mate!!! very detailed and complete. :thumbup:

kingfish · Jun 9, 2010

Will this work on a 2001 525i bimmer that has a bad pusher fan in front of the radiator. I have taken my bumper off before so I know how to do that. But is that the only way to get to the pusher fan? robertlking@verizon.net

jcvara · Apr 30, 2011

Yes, great write up and definitely money and time saving. The only thing that I noticed was the torx bit is actually a 47 and not a 45. Thanbks alot and that was one of the best waters I have ever enjoyed after a job.

osegardm@gmail. · Jun 11, 2011

Great DIY

Thanks for the great instructions, saved me about $350. I have a 2002 530i and the instructions for this apply without many differences.

daw · Jun 11, 2011

Actually, the Torx bit is a T50. You can of course get a smaller one to go in, but the 50 is the perfect fit.

Jimmys 530i · Jun 12, 2011

Great write up.

bluebee · Jun 12, 2011

For the record, since this is an old thread resurrected, here are some of the links for aux-fan debug & repair:

- How to test the cooling system auxiliary electrical fan (1) (2) & the infamous fuse 75 (1) & the aux fan relay (1) and a good DIY (1)

Stillmatic718 · Jun 20, 2011

Just completed this project. Very easy thanks to this DIY and my BlackBerry Playbook. Took me about an hour, thank you.

rdeleon11 · Sep 29, 2012

Thanks for the write up with Pics...Going to Replace my now...will let you know how it goes.

Went perfect! AC blowing nice and cold. While the headlights were out I Purchase a 3M headlight restoration kit...they look brand new!

Talh3 · Nov 22, 2012

I have a 1997 540 I e39 and am in the middle of replacing my auxillary fan. I don't see the t45 bolt ? I was wondering if mine had on ? I've got my headlights out can some one please help? Thanks Tal.

Talh3 · Nov 22, 2012

Problem solved!! I removed the grill and found the bolt!!!! This thread is amazing, I finished the job!!! Thanks again Talmadge.

bluebee · Apr 15, 2013

For the crosslinked record, JimLev offers good advice here for discerning aux fan types:

JimLev said:
Did your fan motor look like this with these color wires coming out of it?
If so, you have a PWM fan.
The older fans are 3 speed that only have 2 wires ans use relays and resistors to switch speeds.
The resistors are mounted to the fan frame.

See also:
- How to test the cooling system auxiliary electrical fan (1) (2) & a DIY for how to replace the aux fan (1) (2) (3) & where is the infamous auxilliary fan Fuse F75 (1) & where is he aux fan relay (1) & an exploding aux fan noise situation (1)

EDIT: I just noticed the excellent pictures in the OP are offsite, so, since offsite links are ephemeral, I am taking the liberty of appending them here, in the order they were posted, so that future users would have the benefit...long after we're gone.

Bimmer Bob · Jun 4, 2013

Just done this job on my 2001 M54 Touring.

I have the PWM e-Fan with three wire connector.

The DME had a code for no response from E-fan.

Another post I found suggested checking for the control square wave with an oscilloscope which I did.

INPA has an 'ACTIVATE', 'E-Lufter' facility for simulating fan speed demands from 10-90%.

The signal wasn't present at the fan connector, but I did find it in the e-box with the DME.

I examined the connector wiring, and sure enough it was corroded about 4" down the cable and broke without any effort.

A new piece of wire spliced in, and it's all over.

Looks like I saved a couple a hundred bucks!!

This is a common theme with BMW. Lots of clever wiring which doesn't stand up to the weather

jcavender · Jun 23, 2013

Thanks SleekBMW

Excellent post. I lost my A/C yesterday afternoon, and with the help of this forum, did plenty of troubleshooting last night. Went by BMW and picked up the Aux Fan Assy this morning (OUCH), and did the deed this afternoon. I'm pretty mechanically inclined, have re-built a few Camaro's etc... This is my first BMW, enjoy the car, and was very pleased with the ease of this job. Took about 1.5 Hrs total. Would have been done sooner but noticed when I was putting the Driver headlight back in that the air intake hose was laying on the floor next to my front tire... Oops. Off with the bumper again, and all done now. Took it out to dinner, ICE cold A/C. Thanks for the excellent article, and I look forward to doing some customizing soon. I'll be reading up on some of the posts here. If anyone needs any info on the 2001 E39, just hit me up. I'll help where I can. Thanks, Jim

rcatank · Jun 23, 2013

Where is the bumper shock absober? I can't remove the driver side of the bumper and both T50 bolts are off as well as both fender liners and front 4 plastic rivets.

jcavender · Jun 24, 2013

bumper shock

The bumper shocks are bolted directly to the front core support. Once you have the two T47 bolts removed, you may have to give a little "jerk" on the bumper, but it should come off with no problem. Actually a very well engineered setup.

chocodile · Jul 4, 2013

Thanks for the great write up and everyone's replies. I replaced my auxiliary fan last weekend, and it was a total breeze.

I "cheaped out" and bought an aftermarket fan (Dorman). But it fit perfectly. The only difference is that the electronics (not sure what its called) are not housed in the electric motor assembly. I read on another forum that this was a problem, and it fails after a year or so. I'm keeping my fingers crossed...

Another thing I've read is that the fan is overly noisy. The new fan is much louder than the original fan, but its not noticeable when you're inside the car.

Finally, the only problem I had was that a plastic clip on the shroud protruded just a bit too far, and rubbed on the fan. I ended up heating the clip with a heat gun, and bent it back out of the way.

Thanks again, everyone!

veneskey · Jul 15, 2013

Thanks for this information. It took me 2.5 hours. I bought my replacement fan off parts geek. I have a set of Bentley manuals, but your post helped the most . Thanks

Bennt771 · Jul 29, 2013

Just did this with your help.... Thx. !!

bluebee · Sep 18, 2013

For the record, this is good information added recently:

JimLev said:
If the temp gauge gets up to 3/4'ers the fan should be on high speed! Which is stage 3. There are no resistors in the circuit for high speed.
You could have blown fuses, bad relays, or the aux fan motor itself could be bad.
You could also have bad resistors or a bad temp switch in the side of the radiator, best to have someone trouble shoot and find out what parts are bad unless you just want to throw parts at it.
Here's the circuit for the 3 speeds. Ignore the notes, they were from helping another person.

rbbmw67 · Apr 5, 2014

Aux Fan Troubleshooting

First of all, I'm new to this community and just want to say that I appreciate the level of support everyone have contribute in efforts of building this knowledge base.

Situation:

I currently own a BMW e39 Japanese version and experiencing intermittent overheating. As the weather here is starting to get warmer (60-95 degrees), this will turn into a major issue. With the information provided in this thread, here is what I preformed

- Start the car and turned on the A/C and the aux fan come on (low or mid speed)

- Turned off the A/C and observed the fan stop oscillating about 5 seconds later

- Let the car continue to run idle for about 30-40 min and observed the temp gauge slowly climb forwards the red. According to research the aux fan should automatically energize at a high speed once the temp gauge reach from the 12:00 position to the 3/4 position, not reaching the red zone

-i will test the applicable fuses (7,20,22 and 75) for GP, but I have the following questions that I hope someone can back to me when convenient

1. In accordance with the schematic provided in this thread, is it necessary to test all of the fuses? It appears that fuse 75 (50 amps) may be the only applicable one for this situation

2. Does anyone know average cost for this fuse? I would like to compare to japan prices

3. Believe I can rule out the two resistors that are mounted in front of the aux fan? In accordance with the schematic it appears the supplied voltage for aux fan high speed operation, the resistors are bypassed.

4. If fuse 75 is good, is the aux fan relay the next point of failure? or the temp sensor?

5. Could someone send a pic of where this relay is located?

Thanks to all for your continuous support

Rbbmw67

JimLev · Apr 5, 2014

Need to know if you have the PWM fan or the 3 speed fan.
What year is your car.

rbbmw67 · Apr 5, 2014

reply to jimlev

The year is 1996 525i not sure on the type of fan

E39 Auxiliary Fan DIY write up-With Pics.

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