Auxiliary fan not working when AC on, but works when temp is high

My auxiliary fan is not working when I turn on my AC. The snowflake button light does light up green but I get no cold air (I do get air, but not cold air). The weird thing is that the auxiliary fan does work whenever the the temp gets hot. Any idea what may be causing this? It's scorching hot here in Cali and I need my AC

Thanks!

Get your AC system checked

Is it gassed and the compressor kicking in?

I kind of have the same issue, my aux fan does not turn on when I have my air on but I DO get cold air. My air is really cold but the aux fan never turns on. My temp has always been dead on in the middle. Any ideas?

Originally Posted by makaveddie81

My auxiliary fan is not working when I turn on my AC. The snowflake button light does light up green but I get no cold air (I do get air, but not cold air). The weird thing is that the auxiliary fan does work whenever the the temp gets hot. Any idea what may be causing this? It's scorching hot here in Cali and I need my AC

Thanks!

Low speed fan relay. It's a $20 part. DIY.

FYI - disable A/C (turn off snowflake button) if cruising below ~20 MPH with the aux fan inop. The high pressure that results from low / no airflow over the condenser will eventually damage the compressor.

-Doug

Originally Posted by Pirate_copy

Get your AC system checked

Is it gassed and the compressor kicking in?

How do I know if the compressor is kicking in? Any particular noise I should be paying attention to?

Originally Posted by dwvcfii

Low speed fan relay. It's a $20 part. DIY.

FYI - disable A/C (turn off snowflake button) if cruising below ~20 MPH with the aux fan inop. The high pressure that results from low / no airflow over the condenser will eventually damage the compressor.

-Doug

So the aux fan operation is not dependent on the condition of the ac compressor? I've read something about fuse 39 having to do something with it.

Originally Posted by makaveddie81

So the aux fan operation is not dependent on the condition of the ac compressor? I've read something about fuse 39 having to do something with it.

Do you know the part number for this relay? I am looking on realoem but I can't find a description.

http://www.realoem.com/bmw/partgrp.d...98&hg=61&fg=25


What does fuse 39 do?

I dont remember exactly where I read it but its either fuse 31 or 39 and it has something to do with the a/c or aux fan...

I just looked at my aux fan, man that **** is retarded. I guess the person that had it before me before to rig with it and I have a relay that connects to my aux fan zip tied near my compressor.

I am guessing that it has gotten wet a couple of times and is now failing. Could that be the issue? Would it be a smart idea to just get a switch for my aux fan and rewire it all or should I replace that relay?

Originally Posted by Soviet1942

I just looked at my aux fan, man that **** is retarded. I guess the person that had it before me before to rig with it and I have a relay that connects to my aux fan zip tied near my compressor.

I recommend restoring the car to the original working order.

Here are some older entries in my blog about troubleshooting and replacing the original relay (located in the fuse box):

http://www.dvatp.com/bmw/maintenance/e36/2006/07/25/
http://www.dvatp.com/bmw/maintenance/e36/2006/08/08/

I should point out that the troubleshooting in the first entry was simply to determine if the fan itself was bad. The fan ran in low and high speed modes when I troubleshooted it, but only because I was getting lucky -- the relay contacts were intermittent. I didn't know that at the time. My tech later diagnosed it as a bad relay because he had seen this many times and took the relay apart to verify the problem.

If you are going to replace the relay, I recommend you replace both low and high speed units. While the low speed relay takes all the abuse and tends to fail first, the high speed relay is critical if you live in a warm climate or do lots of city (stop/go) driving.

-Doug

Originally Posted by Soviet1942

Do you know the part number for this relay? I am looking on realoem but I can't find a description.

http://www.realoem.com/bmw/partgrp.d...98&hg=61&fg=25

BMW Part 61361389105

-Doug

Hi,

I'm from Belgium.
I drive with a e46 320d automatic 2004.

I have similar problem like above but different.

When i put on A/C , i see and hear the fan turn, but when temp outside is hot ( even when very hot!), the fan doesnt turns! The temperaturemeter in dashboard stays in middle, doesnt go to red.

Most of the cars that stays on red traffic light near me have turning/blowing fans, but fan of my car doesnt nothing!! Only if i put on the A/C.

Who knows whats the possible problem.

Thank you.

Old thread but I was wondering if some one can guide me through , I just got my cooling system overhaul done with no fan change. The temp gauge go further more than the middle with a
A/C on once I turn it off the temp gauge back in the middle. Is it fan issue, do I need to change it or it's possibly relay and fuses? Any help would be appreciated be fire I spend money on a part that's not the issue.
Thanks

Originally Posted by momo_oo[][]oo

Old thread but I was wondering if some one can guide me through , I just got my cooling system overhaul done with no fan change. The temp gauge go further more than the middle with a
A/C on once I turn it off the temp gauge back in the middle. Is it fan issue, do I need to change it or it's possibly relay and fuses? Any help would be appreciated be fire I spend money on a part that's not the issue.
Thanks

I would 1) rebleed the cooling system just to make sure you have all the air out

2) Check and ensure the aux fan is spinning when you have the AC on. Does the fan spin when you don't have the AC on?

If you didn't have this problem before, then it's likely something you did in the process of your cooling system, as it should work better now, and not worse. If you didn't touch the fan or the relays, they shouldn't be working any better or worse than they were before your cooling system job.

I know this is an old thread, but figured I'd hit this before trying a new one.
Here's the situation. I found that my aux fan isn't turning on with the AC, so I tested the unit by grounding the high and low speed seperatley to the temp. switch to see if the fan is still good. I believe the high speed is working as it kicked on when grounded, haven't had any overheat issues. Couldn't get the low speed to kick on when testing with ground to temp. switch. Heard the click at the relay box when grounded out though. So, I figured it was the low speed relay for the fan, replaced it with a used one that was from a working unit. Turned the AC on and waited for the fan to kick in, didn't happen. I wondering if anyone can help with any info on this. I'm at the end of my rope. Thanks in advance for any assistance.

Sounds exactly like a faulty low-speed relay. Mine did the same thing, and it was in fact the low-speed relay. Are you positive that the relay you swapped with is a functional unit? Did you try swapping your high-speed relay into the low-speed relay location?

Well, I'm thiking it may be the high speed now, but I'm not sure. I tested the circuits from the fan by grounding each. One turns the fan on, the other didn't. Can't tell by speed wether it's the high or low that is running. So, I'm guessing the fan itself is fine. I went and got the low speed relay, used, but it was actually a different part number than what is in my car. I previously had the same relay (same part number) in the AC compressor and low speed relay slots. The compressor runs fine, so that pushed me toward the low speed relay being the issue. But when I swap the relays from the compressor and the low speed fan (same part #), the compressor runs with both relays. So, I'm guessing that both the AC and low speed relays are fine, and it may actually be the high speed relay that is crap.

sorry to revive this old thread, I have a issue myself too but in this case the fan always run at high speed right after I star the engine.. I am thinking is a relay but then the fan should not spin at all

Yes, check your relays. You have two: one for low-speed, and one for high-speed, and they are located in the black box under the hood, near the firewall, on the drivers side. Normally, the auxiliary fan does not turn on unless A) you have your A/C turned on (and your A/C system is working properly), or B) it's a very hot day outside. The A/C and warmer temps will kick on the low-speed setting. I can't imagine anything short of racing or a desert triggering the high-speed setting. I've driven my car in 103 degree heat and the high-speed setting never kicked in, and know my relays work because I tested them. Your aux fan shouldn't be engaging at all during start-up unless you have your A/C turned on, and even then, it should be the low-speed setting at that point.