my aux fan is not working nor turning on when the a/c is on. I replaced the fan switch that goes in the lower hose attached to the rad when I did the cooling system overhaul.
what else could it be the cause?
how do i directly power it up?
I made it spin, it's not hard to move it. I checked the fuses...well sort of. Of all the fuses that apply to the aux. fan I could only check #20 (7, 20, 22, 75) #7 and #22 don't have fuses but I coud not find #75.
i just read this thread about fuse 75 and the heater blower not stop blowing after the car is shut off http://www.bimmerfest.com/forums/showthread.php?t=419456&highlight=fuse+75.
my problem is the aux. fan, the one in front of the rad. I will try to find fuse 75 in the back of the glove box like the other thread said it was.
You'll find it on this thread: You don't have to remove the glove box. Just slide the black panel underneath, crawl under then look up and you'll see it.
does anybody know what wires are what in the connector? i have the same problem and found the connector, didnt have time to check for power to the fan, but i'll do that tomorrow, i'd like to know which wires are what though incase i need to hot wire it to check the motor.....
aaaahhh I love this forum!!! it never ceases to amaze me. no need to buy the whole aux. fan and spend $300+ dllrs. you can change the motor for about $90. thanks a lot.
Don't get excited too soon! That DIY by "PENER" on bimmerforums is for 1997-98 models.
Your 1999 model has a different setup. Search for info. Very often the whole assembly has to be replaced. But again check to be sure that the Aux Fan is the culprit.
The 1999 Aux Fan is pricy though, about $320-350 range or so. Check realoem.com for PN.
i haven't been able to locate the fan motor by itself. i went to autozone and they don't carry the siemens motor anymore. I've searched online but nothing yet.
Here is my two bits worth. The aux fan on my 99 528 came on nearly all of the time when I first bought my car and I just thought this might be normal. As it ultimately turned out the reason it was coming on all of the time was that it was defaulting to the radiator temp sensor. But, when I overhauled my cooling system I found that the sensor on the bottom radiator hose was unplugged. So, I plugged it in and then the fan would not come on at all. I replaced the sensor with a new one and still no fan; no matter how warm the engine got or how high the pressure in the AC. After driving myself nuts in every way trying to figure it out, I finally took it to a high quality indy shop. They hooked it up to their super scanner and got a message that an aux fan code was missing in the control module. They disconnected the battery for ten minutes, reset the codes and now the fan works just fine.
from what i can see alot of people have had good luck reviving their non working fan motor just by cleaning it out. i'm going to give that a shot. i have the old resistor style 4 plug fan, so i can get a replacement motor for pretty cheap if it doesnt work out.
UPDATE:
I installed the new bmw aux. fan (oem) and my a/c is working good again and blowing cold air. I made sure the new fan turns on before putting everything back together.
The fan is controlled by the dual temp switch on the side of the radiator and the HVAC system.
Stage 1 is low speed from the HVAC panel or the 91 deg switch on the radiator and relay K21.
Stage 2 is controlled by the AC high pressure switch and relay K22.
Stage 3 (high) is controlled by the 104 C deg switch on the side of the radiator and relay K201, which gets power from fuse F75 (50 amp) behind the glove box. F20 and F105 powers K201.
You said the fan comes on when you turn the AC on so Stage 1 (low) is working which means the 2 resistors are good.
Pull the connector off the dual temp switch and jump it to see if you can get.
Jumping pins 1 to 2 should make it run at high speed and pins 1 to 3 for low speed.
I'm having a problem with my aux fan too. My aux turns on and goes off but when it kicks on it makes a very loud noise and sounds like it is straining and the car doesn't over heat. Does anyone have any idea what it could be or what I should do???
Mine did that just before it died, mine would turn on, but would stay on the highest fan speed setting. Sounds ridiculously loud right? The cheapest OEM fan i've found is from ecstuning, or just get a used one for cheap.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
BimmerFest BMW Forum
11.4M posts
753.1K members
Since 2001
A forum community dedicated to BMW owners and enthusiasts. Come join the discussion about Bimmerfest events, production numbers, programming, performance, modifications, classifieds, troubleshooting, maintenance, and more! Bringing the BMW community together.