Official Electric Fan wiring thread!

[bsturman92]

It was my stock switch for my 318is.. and my dumb ass art it outside and left it for two days and it rained.. its all krusty now I don't wanna put it back k in

[RoadHazard]

What did you have in there before the new radiator switch? Can you put it back and see what will happen?

[bsturman92]

Hey guys been postin in many threads and still finding nothing... My 318is I installed a Volvo fan and wired it to the aux wiring... Worked perfect but would have to hit a/c button... Finally ordered a three prong 80 88 switch from 318ti and now won't work at all.. Weather I hit the switch or not.... Now heres the catch..... The ONLY wait works... I have to completely disconnect the wiring for the fan and unplug my battery,... Re-wire the fan and hit a/c button and it works for literally 5 seconds then shuts off completely and won't work again.... All fuses are totally fine none are blown.... I'm lost as hell and need to get this working... I turned my car on and in plugged both hi speed and lo speed relays and none of them click... Please throw ideas at me cuz I'm over this... Been months now and posted in many threads

[Link]

Well then I will leave it as it is for now, and if the fan is not turning on at the right times I will then change it up some. Does someone know what the stock temp the fan turns on low and then high at? If this does not work I will wire it as the first post says and only utilize high speed.

Thanks!

[RoadHazard]

Yes. Blue go to red on stock fan wiring. Black go to brown.

And no, you don't need to do anything to the radiator switch and its wiring if you already have everything.

The 80-88 degree switch will make the fan turn on sooner. But it being a 2-prong means that you can only run the fan at 1 speed. Stock is a 3-prong and when utilized with the fan resistor allows the fan to run 2 speeds. So, do you have to make changes to the radiator switch part? The answer depends on how you want your system to behave.

[Link]

So under a great deal of reading on this I am this far:

On a 1991 318i behind the driver side headlight there is a plug.
Body side: Black/Blue, Black/Green, Brown
Fan Side: Brown, Black, Red

All of it runs to a resistor, then the red and brown wire go from that to the stock fan.
My SPAL fan has a Blue positive wire and a Black negative wire.

Can I just simply wire the Red to Blue and the Black to Brown?

If that works, then what needs to be done to the radiator plug on the passenger side of the car with a Brown/Black, Green/Black, and Black wire at it?

I don't see why I can not leave that as is and why I must use this part # 61-31-1-364-272-82, the two prong 80-88 switch.

Can someone help clarify some of this?

[RoadHazard]

Link,

BK/GN is also a +12V wire. The difference is they are turned on at different water temperatures.

Go back one page and read post#148 and see if that makes any sense to you. Your fan's blue wire is the same as the red wire coming out of the fan in my diagram.

The fan switch, either 2-prong or 3-prong, goes to the radiator. You should already have a connector for it behind the RH head light. It's a black connector similar to the fan connector. See the diagram in the 1st post for wire colors.

[Link]

Anyone got an answer to this^^^

[Link]

Alright so I am still lost on this whole fan thing...

What I know... my fan has a Positive (Blue) wire and a negative (black) wire. I have a 3 wire plug behind my drivers head light with a brown (ground) and a Blue/Black and a Black/Green wire running to it.

What I think I know... The Blue/Black is a 12+ positive wire.

What I need to know... What is the Blue/Black wire, what is the Black/Green wire and where do I put the "Auxiliary Fan Switch 2-Prong" and what wire does it run inline with?

Thanks for any help!

[Link]

Alright so I am still lost on this whole fan thing...

What I know... my fan has a Positive (Blue) wire and a negative (black) wire. I have a 3 wire plug behind my drivers head light with a brown (ground) and a Blue/Black and a Black/Green wire running to it.

What I think I know... The Blue/Black is a 12+ positive wire.

What I need to know... What is the Blue/Black wire, what is the Black/Green wire and where do I put the "Auxiliary Fan Switch 2-Prong" and what wire does it run inline with?

Thanks for any help!

[bsturman92]

Ok EVERYBODY i need your help please!! I read through this whole thread and still having issues.... Please read this and tell me what you think,

So I have a 1991 318is wanted to do an electric fan swap from a Volvo. I got the fan. The only thing I did was cut the three wires at the aux fan and wire them directly to the Volvo fan.. It worked perfect and would keep me car cool for EVER. Except I would have to hit the a/c button to activate it... Wasn't a problem but my a/c doesn't work and at a stop while idling I would hit the switch and it would draw a lot of power m make my idle drop real low then go back up. (Just annoying as he'll) so finally I opted to buy a 3 prong switch from a e36ti which as we all know is rated lower temp.... So I unscrewed the old switch on the side of the radiator (big mess coolant drained out.. Good or bad? Car totally cold) and then installed the new switch and plugged my stock 3 prong plug right in....... Now the fan will not work what so ever no matter if I hit the switch or anything.. The fan works I hooked it up to battery... Someone please tell me what to do to figure this out.. I want it to work on its own... Very hot where I live and temp will slowly increase at stop lights ... Please help guys I'm going crazy

[AirplaneBuilder]

I used my stock AC fan and put some brackets together from bits of metal and mounted it up straight to my M42 radiator nice and solid and just plugged into the plug under the driver headlight so it all works fine now, i just need to push the snowflake button and bam my S50 cools. Its a redneck way to do it but it cost me nothing and super simple to do and if the fan ever fails there is unlimited amounts of used AC fans at junkyards for dirt cheap but since the stock fan has been working since 89 i assume they are pretty well built to last that long.

[mtlbloodshot]

I wish someone would post a step by step pictured DIY of this.

[BlapBlap]

I did everything that was said by the OP besides putting in the 2 prong temp switch, but when I turn my key on, the fan turns on right away...any ideas why that would happen?

I have another E30 thats wired up the exact same way and I just use the A/C button to turn the fan on.

[RoadHazard]

That's exactly how it's supposed to work when you turn on the AC, i.e. power to the low speed and no power to the high speed. If that black wire is terminated at the fan plug then it's very likely to be the same as BK/BU because your BK/GN works exactly the way it's supposed to.

At this point, I would finish the loom first and see if everything is working or not. Run the car to temp and see if then fan turns on at both speeds. When the water temp needle points slightly before 12 o'clock, the fan is supposed to run at high speed.