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Taurus fan wiring (deactivating a relay)

AIbandit

AIbandit

NAXJA Forum User
NAXJA Member
Location
Chico, CA
Taurus fan is a 2speed fan
I need to deactivate lowspeed when highspeed is activated. I've looked at quite a few diagrams for it and have seen mixed/ bad wiring. One thing I do not want is my 140amp spiking high power coming from a 40 amp relay.

Materials:
Low temp- Hayden adjustable
High temp - Stock Aux
150 amp Solonoid
2x 40 amp 5pin bosch relays
Fire extinguisher

So I've got this, I'm not happy about the 40amp being the power source for low but that's why I'm posting. Any better ways to do this?
NkMQxou.jpg
 
40 amps at 12V = 400 watts. That is over 1/2 horsepower for the fan. That should be more than enough even for the high setting.

You should be able to use the brown and green respectively for the low and high terminals on the fan.

My recommendations are based upon the fan having a ground (not shown on your schematic)
 
The fan operates at 40-60 but initially spikes 140 when turned on. Yeah fan is grounded and everything is fused accordingly.
Thank you.
 
The leads Im using on mine are for fan 1 and fan 2, I dont believe fan 1 shuts off when fan 2 starts, so it would be feeding both circuits presumably when high speed is called for. Havent noticed any issues. Unfortunately the jeep computer provides power to the relay when fan is called for instead of ground. If it was ground you could just run the volvo relay and be done with it

You could use two 80a relays if youre concerned with the inrush causing an issue. I seriously doubt the factory relay was any higher than that and they worked fine
 
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Yeah I've been going through a lot of Taurus fan threads. The consensus in the mustang world seems to be low needs to be deactivated but I've seen plenty that just let it run.
 
Mine is the volvo version, but its the same fan motor so it shouldnt make any difference.

If you really wanted to get the low disconnected when the high comes on, I guess you could route the high signal through another relay (this one would normally pass power through to low except when energized) to shut down the low fan. So you would have a third relay, high signal in/out 85/86 and the power wire for low in 30/ out 87a.
 
I would ignore the inrush current unless I either cooked fuses or wiring, but that's just me. The factory parts to run these fans were not terribly impressive, but seemed to hold up pretty well. I've since abandoned any more work on my fan setup, but I though the Volvo relay block was the most attractive option, given that you could use extremely short and simple wiring.

I would also take Old_Man's advice over mine, just sayin'.

edit- Just in case we aren't all reading the same threads, I would only use a setup that started the fan in low speed, then switched to high. The BMW 3 wire, 2 stage temp switch, with Volvo relay block, and 2 speed fan, or an equivalent. I have a variable speed, soft start, controller even for my weenie little fan, because it is basically worry free. That's why the inrush current on high isn't something I'd worry about; I'd just avoid that situation.
 
Last edited:
hubs97xj said:
I would ignore the inrush current unless I either cooked fuses or wiring, but that's just me. The factory parts to run these fans were not terribly impressive, but seemed to hold up pretty well. I've since abandoned any more work on my fan setup, but I though the Volvo relay block was the most attractive option, given that you could use extremely short and simple wiring.

I would also take Old_Man's advice over mine, just sayin'.

edit- Just in case we aren't all reading the same threads, I would only use a setup that started the fan in low speed, then switched to high. The BMW 3 wire, 2 stage temp switch, with Volvo relay block, and 2 speed fan, or an equivalent. I have a variable speed, soft start, controller even for my weenie little fan, because it is basically worry free. That's why the inrush current on high isn't something I'd worry about; I'd just avoid that situation.
Click to expand...

What brand of variable speed controller do you have? I need to get one but I prefer the sensor to be threaded into the water jacket.
 
I am using this, but I didn't pay that much, and honestly don't think I could recommend it at this price. There are 2 kits, and the difference is the sensor, but the cost difference has historically been more than the cost of the sensors, which is silly.

http://www.summitracing.com/parts/flx-31163

Hindsight being what it is, I think I should have waited for one of these.

http://www.dccontrol.com/relay_controllers.htm

edit- I don't recall them having so many parts at the time, but I feel like this is at least as good, or better, than what I have. Certainly more modular and rated for higher amperage fans, which I think is probably a lot more attractive to most people modifying station wagons and ugly coupes...

http://www.dccontrol.com/constant_temperature_controllers.htm
 
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AIbandit said:
The fan operates at 40-60 but initially spikes 140 when turned on. Yeah fan is grounded and everything is fused accordingly.
Thank you.
Click to expand...
Exactly how are you measuring this? What gage of wire are you running?

Not trying to be an ass, but I am an Electrical Engineer and something doesn't add up. I did a quick check online and the max amps at high speed should be 28-33 amps. Don't worry about the inrush if you use a good Bosch 40A relay. They are designed for that.

Personally, I wouldn't run anything less than 10 gage wire.
 
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I believe your numbers are wrong and that you are over thinking this whole setup.

If you're dead set on cutting low power when engaging high power then your relay setup looks correct but I would delete the solenoid.

It's simply not needed. They are not used on the Taurus either. Just relays.
 
AIbandit said:
Taurus fan is a 2speed fan
I need to deactivate lowspeed when highspeed is activated. I've looked at quite a few diagrams for it and have seen mixed/ bad wiring. One thing I do not want is my 140amp spiking high power coming from a 40 amp relay.

Materials:
Low temp- Hayden adjustable
High temp - Stock Aux
150 amp Solonoid
2x 40 amp 5pin bosch relays
Fire extinguisher

So I've got this, I'm not happy about the 40amp being the power source for low but that's why I'm posting. Any better ways to do this?
NkMQxou.jpg
Click to expand...
What about connecting the low speed side relay coil ground to the high speed fan power lead. When there is no voltage on the high speed motor windings the relay will ground through the windings. When the high speed is powered the ground no longer exists, and the low speed coil circuit is broken. Basically it's the same set up used by Chrysler on the fog lamp circuit, but instead of the drivers side high beam lamp you're using the high speed motor windings.



NkMQxou_zps68890b59.jpg
 
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Is that output grounding the case for all relays/solonoids? Sounds like the best route.


Fire there's videos on you tube showing the draw. Most people use an 80 amp relay though.
 
If low can ground off of the solonoid then the first HIGH relay is not the indicator anymore making it irrelevant?

KMDZLep.jpg
 
I tested and neither post grounds when not activated.
 
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