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Electric Fan Conversion

I have read through the entire thread, and I have yet to find an answer to one set of questions. When using the factory fan control wire from a 9xx ecu how are people tying into them? Are they running new wires all the way back to the ecu plug and directly splicing them into ecu pin #7 and #22, or using vampire clips? Is there a spot closer in the engine bay the wires from pin #7 and #22 go to? And finialy is there a place I can find the wiring schematic for my '91 945 so that I can truly verify that pins #7 and #22 are for the fan control? Thanks, if I can figure this little detail out the install will be a snap.
 
I have read through the entire thread, and I have yet to find an answer to one set of questions. When using the factory fan control wire from a 9xx ecu how are people tying into them? Are they running new wires all the way back to the ecu plug and directly splicing them into ecu pin #7 and #22, or using vampire clips? Is there a spot closer in the engine bay the wires from pin #7 and #22 go to? And finialy is there a place I can find the wiring schematic for my '91 945 so that I can truly verify that pins #7 and #22 are for the fan control? Thanks, if I can figure this little detail out the install will be a snap.

First, I don't believe the 940 had ECU fan control until '93 or '94, and then it needs to be a 9XX ECU, which the '91 may not have fan control pin-outs or wiring and youy will have to add the wires.

In any case, the wires from the relay are ground wires completed through the ECU, so all you need to do is run the blue/blk or wht/blk to those pins. Check at the pins to see if the're grounded after the engine is warm and at temp. Note: the ground can be either/or the temp sensor in the head OR the radiator mounted sensor. It's wired in parallel.

Normally the high speed (blue/blk IIRC) is wired to the hot-side radiator switch and/or the A/C pressure switch, and low speed goes through the ECU
 
finally got around to putting in a 2 speed 940 fan on my 87 244. Used the 940 relay with a Saab T in the lower hose. It is a sweet setup. I tried one on the 91 with the adjustable temp hayden and blew a relay 600 miles from home. Lucky it was in the fall or Also to the time to clean the radiator that had nothing for a few years. Going to the same setup on my 91 since it works so well with just the low speed hooked up. Should be able to run a wire to the green wire on the AC compressor for the high speed. Thanks for the pictures of the relay on page 14.
 
The wiring doesn't look too bad to me, but what about a fan shroud that will make use of the full radiator? Are we talking 960 radiator+shroud? If so, will it fit into a 90 740T?

What I'd love to find is a radiator switch that has 2 switches inside that close at different temps. It seems simpler than a fan controller.
 
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The wiring doesn't look too bad to me, but what about a fan shroud that will make use of the full radiator? Are we talking 960 radiator+shroud? If so, will it fit into a 90 740T?

What I'd love to find is a radiator switch that has 2 switches inside that close at different temps. It seems simpler than a fan controller.

I use a 940 fan on a 240 so I had to trim some. May be a good fit on a 740.
 
The wiring doesn't look too bad to me, but what about a fan shroud that will make use of the full radiator? Are we talking 960 radiator+shroud? If so, will it fit into a 90 740T?

What I'd love to find is a radiator switch that has 2 switches inside that close at different temps. It seems simpler than a fan controller.

Re-use the stock shroud, the 940/960 shroud is way too thick to fit pre-92 7/9 with the mechanical fan.

As for fan switches you can use a t-fitting and switch (make sure it's not the one rated at 115*c) from a saab 9000. Put it inline one of the rad hoses and wire that to the low speed side of the volvo relay. Then if your radiator has the switch for the baby pusher fan in front of the a/c compressor, disconnect that and hook your high speed side to that switch.
 
Re-use the stock shroud, the 940/960 shroud is way too thick to fit pre-92 7/9 with the mechanical fan.

As for fan switches you can use a t-fitting and switch (make sure it's not the one rated at 115*c) from a saab 9000. Put it inline one of the rad hoses and wire that to the low speed side of the volvo relay. Then if your radiator has the switch for the baby pusher fan in front of the a/c compressor, disconnect that and hook your high speed side to that switch.

The T-fitting would work, but I don't want to add in more things that may break - especially plastic things. I'm thinking more like this:

http://www.alibaba.com/product-gs/474243000/V_W_Radiator_Fan_Switch_85.html

With that(in the right thread pitch and length), splice in a pigtail straight off the relay (and add a dash switch that switches that wire from the sensor to the switch) and who needs a fan controller?
 
The saab t-fittings are metal and aren't likely to break unless if you get one that's corroded to ****.

Not many people use a fan controller, the 2 speed volvo relay covers most everyone's needs.
 
The saab t-fittings are metal and aren't likely to break unless if you get one that's corroded to ****.

Not many people use a fan controller, the 2 speed volvo relay covers most everyone's needs.
 
I've got my fan finished, finally, and it works a treat. I'm using the medium 960 rad (590x420 core), 940 e-fan and relay, and BMW 2-speed fan switch in a T fitting in the top hose.

The relay gets it's power direct from the battery via a 30A slow-blow fuse which sits in a spare fuse holder already on the + terminal. It doesn't run at all while driving, kicks in occasionally in traffic, and it usually cycles itself once after I shut the car off. If it really bothers me I might put the fan on ignition-switched power instead.

GU4Kxl.jpg


Fan
xYofPl.jpg


Relay
zkPfVl.jpg


Switch
mxi3Ql.jpg
 
I've got my fan finished, finally, and it works a treat. I'm using the medium 960 rad (590x420 core), 940 e-fan and relay, and BMW 2-speed fan switch in a T fitting in the top hose.

The relay gets it's power direct from the battery via a 30A slow-blow fuse which sits in a spare fuse holder already on the + terminal. It doesn't run at all while driving, kicks in occasionally in traffic, and it usually cycles itself once after I shut the car off. If it really bothers me I might put the fan on ignition-switched power instead.

GU4Kxl.jpg


Fan
xYofPl.jpg


Relay

zkPfVl.jpg


Switch
mxi3Ql.jpg

what is the the temp switch set on got mine in the lower hose sand love it. Also what type of copler ? Looks billet.
 
I've got my fan finished, finally, and it works a treat. I'm using the medium 960 rad (590x420 core), 940 e-fan and relay, and BMW 2-speed fan switch in a T fitting in the top hose.

The relay gets it's power direct from the battery via a 30A slow-blow fuse which sits in a spare fuse holder already on the + terminal. It doesn't run at all while driving, kicks in occasionally in traffic, and it usually cycles itself once after I shut the car off. If it really bothers me I might put the fan on ignition-switched power instead.

GU4Kxl.jpg


Fan
xYofPl.jpg


Relay

zkPfVl.jpg


Switch
mxi3Ql.jpg

what is the the temp switch set on got mine in the lower hose sand love it. Also what type of coppler ? Looks billet.
 
I've got my fan finished, finally, and it works a treat. I'm using the medium 960 rad (590x420 core), 940 e-fan and relay, and BMW 2-speed fan switch in a T fitting in the top hose.

The relay gets it's power direct from the battery via a 30A slow-blow fuse which sits in a spare fuse holder already on the + terminal. It doesn't run at all while driving, kicks in occasionally in traffic, and it usually cycles itself once after I shut the car off. If it really bothers me I might put the fan on ignition-switched power instead.


Switch
mxi3Ql.jpg

very nice... where did you get the T fitting from?...

some quick research shows that switch to be pretty common in BMW's...

as per napa's info...
Coolant Fan Switch Temp Rating : No. 1 On At 194 Deg. F., No. 2 On At 207 Deg. F.
Coolant Fan Switch Thread Size : M14 x 1.5"

some cross reference on summit for it Beck/Arnley 143-2011520
looks like it was used in everything from the 318 all the way on up to the v12 750 and everything in between from '87-97...
http://www.summitracing.com/parts/BCK-201-1520/Application/?prefilter=0

will def peek under a few bimmers next time i'm at the JY
 
The T fitting I'm using is this one, there are probably plenty more makes available with M14x1.5 thread. The BMW switch is handy because there are plenty in the yards and they're easy to get at (find it in the left rad end tank as you look into the bay), it's on most BMWs made in the 90s that have AC. The temp rating of the switch I'm using is Lo on at 90?C, Hi on at 95?C. There are a few different temp ratings of the BMW switch I think for different applications.
 
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Hey Wooble- Nice to see you over here!

I have a V90 fan with shroud complete with relay wiring which I hope to fit to my 240 soon. This thread has been very useful!
 
FYI some part numbers and equivalents for the temp switch, 22mm thread for the aftermarket 3 row radiator:

Vernet p/n ??? on 92 off 82
NAPA p/n FS150 on 87, off 82 C (198/188F)
FAE p/n 201-0809 on 87, off 82
Wahler VWW022209 on 87, off 82
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I'm using the stock Bosch relay dirrectly from the battery, I don't use a fuse, and wonder why anybody would think they need one, as this power control relay is designed to be a fuse in itself, which is the way it was used in the 940.

Incidentally, the NAPA FS150 crosses over to an Autozone SW533. I've been running it for almost a week now and its working great.
 
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wooble said:
The T fitting I'm using is >this one<, there are probably plenty more makes available with M14x1.5 thread.
Switch
mxi3Ql.jpg
Very good find wooble! I was searching a lot, but almost all T pieces has 1/8 NPT thread. So in the end I bought one of these and redrilled/rethreaded the sensor hole.
 
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