Official Electric Fan wiring thread!

[eternal24k]

For those with 82C temp switches, what temp does yours actually kick on?

I just pulled my 82C FAE/Facet switch and tested it, average temp it kicked on was 90C and turned off at 79C.

Also, blew my 30amp fuse, anyone use slow burn fuses? My father uses them a lot and suggested I use it for this application.


Also, do not bother ordering the Febi 82C from FCP Euro, it is labelled "90-95" and "01102" which would make it a 91C fan according to some cross posting, I told them and told them it should be marked "03280" and they shipped me another 91C switch. I tested both, kick on around 95C

[eternal24k]

i went to install mine via Klug's write-up, but when testing, my fan did not have power when starting the car, so I could not see how starting at at temp would cause issues and went about it the classic way.

Maybe i am missing something

[Kush&OJ]

So i can use the stock e30 A/C fan on the front and just switch out the radiator temp switch for a 3 prong 80*C/ 2speed sensor and I should have enough fan power to maintain a cool engine. Do I need to add a new thermostat also?
I’m running a mechanical fan atm and it sits too close for comfort

[JamesE30]

I know it's an old question, but...

The only thing I can think of is that the trigger voltage/current is almost, but not quite enough to activate the relay.

Thanks for the help, it was indeed not enough voltage. I now have the 12v supply wired direct to the battery. The system works perfectly now, except this means the fan will obviously stay on even after the car is off. So I now have the same problem as “She loved E” below.

Can anyone who used Klug's method help me out? I'm trying to figure out the best place to hook into +12 (always on) and acc in the engine bay. Klug said to hook into the accessory fuse box (little black box next to main fuse box), BUT, I don't have one of those. :( My car is an 89 325is but its been modified pretty heavily by previous owners. Will be poring over wiring diagrams to see if those wires are still under the hood but in the meantime would appreciate any tips.

I have the same problem as this now. My car is quite modified and I don’t have the stock acc fuse box any more, where is the best place to find switched acc power for the fan?

[digger]

What's the best way to get the stock aux fan to run on high with A/C button pressed?
I want the low and high to work as per normal when a/c is not on albeit with 80/88 switch

[TimeMachinE30]

What are factory fan options for an M30 swap if not using a Spal?

[She loved E]

Cancel that, figured it out yesterday. On my car +12 is red, acc is green. My small fuse box is missing but those two wires were there. All hooked up & tested. Fan works great! Thanks to everyone who contributed to this thread - esp Klug for the detailed parts list & diagram.

[She loved E]

Can anyone who used Klug's method help me out? I'm trying to figure out the best place to hook into +12 (always on) and acc in the engine bay. Klug said to hook into the accessory fuse box (little black box next to main fuse box), BUT, I don't have one of those. :( My car is an 89 325is but its been modified pretty heavily by previous owners. Will be poring over wiring diagrams to see if those wires are still under the hood but in the meantime would appreciate any tips.

[mjweimer]

phenryiv1 - I like where you are heading with this and will be watching for updates. I would like to wire up my swap with this same scheme.

Please update this thread when you sort it out!


MJ

[phenryiv1]

My 2.7i swap came with the mechanical fan deleted so I went with an electric fan. I had it running off of a thermostatic controller (temp probe in radiator) with a relay. Unfortunately, the controllers have a reputation for failing, which is what happened to me. The circuit board had continuity issues and the board kept losing power but I never knew if it did or did not have power because hearing the fan run with the engine running was impossible.

So last week I realized that the controller had shit the bed…mostly because I saw the temps shoot into the red and the car pissed coolant from a blown coolant passage. Fortunately the head gasket did not go- the gasket at the TB heater failed first (thank God).

Now I am trying to build a new fan controller based on the 61-31-1-364-272-82 switch in the A/C fan port in the body of the radiator. Plan is to use either one or two 5-pin relays. I can either use a 2-relay system that has an override switch in parallel with the thermostat switch on a single-relay setup OR I can run 2 totally separate parallel relays – one thermostatically controlled and one manually controlled. A single will be easier to wire up but a double relay system has the benefit of redundancy.



Obviously the 30/51 will be fed with a fused 12V+ signal and terminal 85 will be grounded. Terminal 87 will feed the fan when triggered. The assistance comes in two areas: The use of the 87a terminal and setting up “indicator” or “status” lights associated with 87 & 87a.

So the new setup will use an 80*C switch trigger that goes into the A/C port in the radiator. It will supply the trigger to the 86 terminal on the relay. I can also run a simple toggle switch in parallel to the terminal 86 or I can run the second relay. Which would you recommend- two relays with discrete triggers or dual triggers run in parallel to a single relay?

Second question focuses on an indicator or status light. I would like to have a light that remains on when the relay is powered but not triggered by wiring the status light into the 87a terminal and then having it change color or illuminate when the relay is triggered and the 87 terminal fires. Ideally the “triggered” light would be tied across the coils of the fan but that would be too hard to wire up so this is a good (enough) indicator solution. I found something like these:

http://www.alliedelec.com/sloanled-255-12-r-g/70015146/

http://www.dialight.com/Product/Details/557_led_panel_mount_indicators_PMI/5571432203F

If I tie one color into the 87a to show power to the relay and the other color into the 87 terminal to show that the relay has been triggered, that should at least give me an idea of the status of the relay (though obviously not the actual fan), correct? And would that small LED require any sort of diode or resistor? It would be the only thing on the 87a terminal when the relay is not triggered but when wired in parallel with the high-draw accessory fan will it cause issues?

While this all makes sense to me in theory I just don’t understand circuits well enough to have full confidence in the schematic that I drew up in my head.

[bradmer]

Back to the first page bump

Because it's not stickied, yet.
This thread is great, can confirm it comes on a tick below half. Had originally run a toggle switch for manual operation and opted for this instead. Below quoted from OP, thank you Dave.

1: Install fan in car. To Preface a GOOD WORKING factory fan will out cool most aftermarket ones. I run stock fans in almost all the swap cars i do here as they move ALOT of air.
- I should have gotten the the radiator and pusher from the donor car for the swap, it would have been cheaper, factory and less mental anguish.

2: Find stock fan wiring on drivers side under drivers headlight - (BEFORE the plug)

chassis BK/Blue to black on fan

chassis brown to blue on fan

BK/Green did not use.

- Sorry to beat a dead horse man, but when it comes to auto electric I need to be lead straight to it. Noobs. :)

[rustneversleeps]

Ok got my low speed Bosch resistor but it's the wrong one..
The one that i have in the car is the hard wire one Magna would it be ok to use the the Bosch resistor instead of the Magna...

[rustneversleeps]

well reading all this gives me a little insight on how about getting the fan to work thanks god for the Bentley manual it should be pretty easy to trouble shoot..need to be sticky thread..

for the above comment check relay K6 which is the high speed..

[jeenyus]

I tried to simplify this whole process by replacing the AUX fan with the new electric puller fan. I then wired it exactly how the AUX fan is setup, albeit removed the resistor prior to the AUX fan and replaced the 15a fuse in slot 4 with a 30a fuse.

The fan works only when i push the snowflake, but i was really hoping it would turn on when the car reached 80C, like the new AUX switch i purchased. Any idea why it wouldn't kick on automatically when it reaches temp?

Thanks.

[Mark 42]

I know it's an old question, but...

The only thing I can think of is that the trigger voltage/current is almost, but not quite enough to activate the relay.

Hey guys, need some help with a strange problem,
I have wired up my new 16" SPAL Pusher exactly as described by Klug.
I have all new wiring (12GA), a new 82* single speed fan switch, and new relay as pictured below.

With the thermo switch activated (or bypassed) The fan will only turn on if i physically TAP the relay.. with my finger..
Just a light tap does it, but if i don't touch it nothing will happen.
Here is a quick vid showing what I mean.

https://www.youtube.com/watch?v=oTann85ZvhI&feature=youtu.be

I have tried this with 2 brand new relays and they do the exact same thing. The whole system/switch/fan works perfectly, but the fan wont turn on until i tap the relay.. I'm baffled?? Any ideas?

This thread has been super helpful so far so thanks to everyone who contributed!