Author Topic: When does the auxilary fan come on? (Read 5952 times)

91_e30_m42 · « **on:** July 25, 2009, 10:34:25 PM »

i just replaced the thermostat on my 318i and i was checking around, and i realized the auxilary fan in front of the AC condensor never came on. i turned on the AC and nothing still doesnt come on. Do i need to replace it or is there a relay, fuse or sensor i should check

thanks

AcSchnitzer318is · « **Reply #1 on:** July 25, 2009, 10:50:21 PM »

First, check the fuse. If that's not it your resistor probably went bad... replace that and all should be well. If that's not it the fan is the likely culprit.

HATER-PROOF · « **Reply #2 on:** July 25, 2009, 10:54:46 PM »

how long did you allow her to run? make sure the fuse is good.

HATER-PROOF · « **Reply #3 on:** July 26, 2009, 12:31:56 AM »

as stated from *AcSchnitzer318is*" If that's not it the fan is the likely culprit." unplug your aux fan and test it to make sure it rotates from your battery power. Also try to physically rotate the fan and if it turns with-out stopping-----that's where the problem exists.

91_e30_m42 · « **Reply #4 on:** July 26, 2009, 08:59:49 AM »

i let her run for about 30 mins, where would the fuse be, and the resistor

DesktopDave · « **Reply #5 on:** July 26, 2009, 09:35:39 AM »

The most likely fuse is #18 IIRC. Just look to see if they're all good (various circuits use 3, 18, 19 & 20 for the fan per the ETM). The resistor is mounted to the shell of the fan in front of the radiator. It'll be a silver or black cylinder ~4" long screwed to the shroud.

Does the aux fan come on when you turn on your A/C? Then you know high speed is good (unless your A/C isn't charged, that is).

To test both high & low modes, pull the connector off the switch on the upper radiator passenger side. Get a bit of wire and short the center wire (green?) to each of the outer wires (black, black/brown?) in turn. One controls low-speed, the other is high-speed. If both work shorted, test or replace the switch. If only one speed works, it might be the switch, resistor or relay. Low speed is K1, high speed is K6.

I had a heck of a time removing that resistor BTW. I pulled the radiator & condensor out of the way and yanked the entire fan assy. out through the engine bay.

91_e30_m42 · « **Reply #6 on:** September 10, 2009, 08:52:05 PM »

does anyone know where i can get a fuse box diagram

Choking Hazard · « **Reply #7 on:** September 10, 2009, 09:03:14 PM »

Quote from: 91_e30_m42;78239

does anyone know where i can get a fuse box diagram

I think there is one on BMWDIY.com

91_e30_m42 · « **Reply #8 on:** October 22, 2009, 09:07:36 PM »

still cant find a diagram help please

monty23psk · « **Reply #9 on:** October 22, 2009, 09:24:23 PM »

Google e30 etm for the electronic manual. Also the factory workshop manual would have it. Regarding the fan, this is what I would do. First remove kidney grill in front and try to spin it. Does it spin freely? If not, then it might work but will be draggin and be very loud. If it moves freely, I woul either give it 12v at the connector which is behind the driver side lights or use the radiator dual temp switch connector to jump the fan in either low and high speed. If the fan does not move, then it is the fan, fuses or relays. You can always check the fuses first, but the relay will help you as much. Also if all that is good and the diode in the fuse box is bad, the fan will get you juice. Ask me how I know. I can walk you through all those steps.

Just find the fuse panel diagram to fine the right fuse. If it is #18 like DesktopDave stated, you can always look at the box itself with the cover of and see the tiny little number along the fuses on the fuse box itelse. I do know #1 is the passenger side toward front of car.

318isam · « **Reply #10 on:** October 25, 2009, 01:43:45 AM »

Quote from: DesktopDave;75882

The most likely fuse is #18 IIRC. Just look to see if they're all good (various circuits use 3, 18, 19 & 20 for the fan per the ETM). The resistor is mounted to the shell of the fan in front of the radiator. It'll be a silver or black cylinder ~4" long screwed to the shroud.

Does the aux fan come on when you turn on your A/C? Then you know high speed is good (unless your A/C isn't charged, that is).

To test both high & low modes, pull the connector off the switch on the upper radiator passenger side. Get a bit of wire and short the center wire (green?) to each of the outer wires (black, black/brown?) in turn. One controls low-speed, the other is high-speed. If both work shorted, test or replace the switch. If only one speed works, it might be the switch, resistor or relay. Low speed is K1, high speed is K6.

I had a heck of a time removing that resistor BTW. I pulled the radiator & condensor out of the way and yanked the entire fan assy. out through the engine bay.

my aux fan also doesn't come on when i turn on my a/c,so i did the wire short method and the fan doesn't come on at any speed but i can here the relays clicking when i short the wires so i am thinking it's my relays cause i took the fan out to check the connector and plugged a 12-volt power source to the fan and it spun so i know the fan works. my car doesn't have the resistor on the fan so i was wondering if i have to put one on?:confused:

monty23psk · « **Reply #11 on:** October 25, 2009, 08:34:21 AM »

If you want the low speed to work, you will need the resistor. Also the AC will make it work with low speed, so if you dont have resistor, it will not turn on. If you jump the connections from the temp switch connector, you should at least get the high on, but not sure if it would work without the resistor. If the fan works by itself, then you just need to troubleshoot it turning on.

AcSchnitzer318is · « **Reply #12 on:** October 26, 2009, 01:34:14 AM »

If your relays are clicking... they are most likely not the problem. I'd start with the resistor.

xwill112x · « **Reply #13 on:** October 26, 2009, 01:45:50 PM »

lol ever since ive had mine its never worked. fuses, are good..havent really inspected further than that. The temps stay cool, so i dont really care.

monty23psk · « **Reply #14 on:** October 26, 2009, 02:01:57 PM »

Lucky for you. THe aux fan is more for the AC than engine cooling, unless you go aftermarket. Doesn't push that much air.