Bartman Posted August 5, 2005 Share Posted August 5, 2005 Hans, What relay's are you using? I've only wired the high speed of my fan and I wired it using one single POS relay. I'm wondering if I'm not getting enough amperage to my fan and that's why it won't start sometimes. Maybe I need to use two good one's like you did. I should really hook it up the right way like wheelman did and let the PCM control the high and low speeds. Man, it's a good thing I don't do this for a living:icon52: . I was justed searching around the internet, and I found another site where they talk about using a 75 amp rated Bosch relay (0 332 002 156) that supposedly costs around $30. Maybe I should get one of these (or something similar)? Quote Link to comment Share on other sites More sharing options...
Tim240z Posted August 5, 2005 Share Posted August 5, 2005 Bart, What guage wire are you using to the fan. I used a regular automotive relay and used a toggle switch for the high speed on the fan and never had any problems......I also only used a 20 or 25 amp fuse and never blew any. Are you sure that the fan is wired correctly....I have a couple of other Taurus fans if you want to try another (maybe yours has gotten tired?).... Tim Quote Link to comment Share on other sites More sharing options...
Bartman Posted August 5, 2005 Share Posted August 5, 2005 Bart' date='What guage wire are you using to the fan. I used a regular automotive relay and used a toggle switch for the high speed on the fan and never had any problems......I also only used a 20 or 25 amp fuse and never blew any. Are you sure that the fan is wired correctly....I have a couple of other Taurus fans if you want to try another (maybe yours has gotten tired?).... Tim[/quote']My setup sounds identical to what you used, and I'm not having any problem blowing fuses either. Not sure of the wire gauge, but I think it's identical to what was already on the fan. From the searching I've done here and at other sites, most people are connecting two relays in parallel or using one high amp unit (for the high speed setting on the fan). I don't understand electronics enough to know why this is necessary, and what the penalty is for just using one standard relay. If I'm not blowing fuses, does that mean it's not drawing more than 20 amps? If it's not drawing more than 20 amps, is the motor not working as well as it should? Again, it usually seems to work fine. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted August 5, 2005 Share Posted August 5, 2005 With these fans, on high speed, there is no way that can't tell that it is working correctly.....they pull huge amounts of air....it is so obvious when it isn't working right.... Quote Link to comment Share on other sites More sharing options...
Bartman Posted August 5, 2005 Share Posted August 5, 2005 I would still appreciate an explanation about high amperage relays. These Taurus fans are REALLY popular and there are a bunch of forums on the net that praise their performance and value. Everyone seems to have different data, but the consensus is that the draw a LOT of power. Something like 33 amps continuous and up to 100 amps at startup. http://www.pirate4x4.com/tech/taurus/. One article I read claims that it draws 130 amps on startup and 40 amps continuous! http://www.fordmuscle.com/archives/2003/02/electricfan/index.shtml I would think that I have it wired up correctly or it wouldn't work at all. Most of the time it works, and it seems to work well. I would assume that somewhere I have a weak link. I'm using a 20 amp fuse and it's not blowing out. Doesn't that mean I'm not getting enough amperage through it? I don't want to waste money replacing things that don't need to be replaced, but it sure sounds like I need to double up my relay or purchase a higher amp unit. PS - Thanks Hans for letting me hijack your thread to debug my fan install. Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted August 5, 2005 Author Share Posted August 5, 2005 I'm using a 20 amp fuse and it's not blowing out. Doesn't that mean I'm not getting enough amperage through it? Bartman, I have the same question but then my electrical knowledge is also severely limited. Maybe you need to hook up your fan relay directly to a wire from the positive pole on the battery. I'm using a separate 6 gauge wire to feed the 3 fan relays and a 4 th water pump relay. The high speed fan setting was the only one to blow fuses. The relays are just ordinary automotive 30 amp Bosch units. I ran the Z at Irwindale Thursday and got my best ever 60 ft time of 1.39. I raced with the low fan speed and then used high fan speed to return to the pits. Temps never exceeded 170 degrees. When I turn on the hi speed fan my voltage gauge shows a big dip to 13 volts from 14, at idle. It takes more juice to run the fan than all my other electrical needs, including headlights. Hanns Quote Link to comment Share on other sites More sharing options...
Bartman Posted August 5, 2005 Share Posted August 5, 2005 Bartman' date='I have the same question but then my electrical knowledge is also severely limited. Maybe you need to hook up your fan relay directly to a wire from the positive pole on the battery. I'm using a separate 6 gauge wire to feed the 3 fan relays and a 4 th water pump relay. The high speed fan setting was the only one to blow fuses. The relays are just ordinary automotive 30 amp Bosch units. I ran the Z at Irwindale Thursday and got my best ever 60 ft time of 1.39. I raced with the low fan speed and then used high fan speed to return to the pits. Temps never exceeded 170 degrees.[/quote']Congrats on your new best 60 ft time! My relay is hooked up directly to a wire from the positive pole on the battery, but I don't know what brand or amperage it is. It was an elcheapo from PepBoys. I'm still thinking this is the problem, or even if it isn't, that I should replace it with a single high amperage unit or two 30 amp Bosch units like you have. Did you get your's from NAPA? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted August 5, 2005 Share Posted August 5, 2005 Hans, congrats on the 1.39!!! So, how does it feel to be shot out of a cannon? :D Nice clean install on the Taurus fan. Also just put one on an alum 24x19 and wired it to run on high triggered by the ECM. Low speed is triggered by a manual switch for when I am in the pits with the ign off. The 2 brackets at the bottom supports all the weight of the fan and the little tab at the top holds it up against the core. No plastic tabs through the core to damage the tubes. Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted August 6, 2005 Author Share Posted August 6, 2005 Scottie, 1.39 feels awesome. Thanks. Yes, that fan fits your radiator quite well. Bartman, My relays came with my Painless Wiring Harness. Hanns Quote Link to comment Share on other sites More sharing options...
Tim240z Posted August 6, 2005 Share Posted August 6, 2005 Bart: http://www.waytekwire.com http://order.waytekwire.com/CGI-BIN/LANSAWEB?WEBEVENT+L0A89CD04735684005910032+M37+ENG Quote Link to comment Share on other sites More sharing options...
wheelman Posted August 6, 2005 Share Posted August 6, 2005 I just spent the evening chasing down a problem with the fan circuit, turns out one of my relays was bad and it shorted a bunch of stuff together. The symptoms were that the car would not shut down when I turned off the key and the high speed fan circuit was energized all the time. I replaced the relay with a spare one I had after tracing out all the circuits involved and everything works as it should. My suspicion is that the relay was bad right from the start (it was pulled from the donor car) but I can't be sure. It was a bosch unit that was used as a fan controller in the Caprice so I think it can handle the load of the Taurus fan. If the new one fails in the same manner I'll let you guys know. On a different but related topic, when I originally wired up my alternator it would not charge the battery but put out 13 volts. It's a high output (140 amp) single wire unit used in the cop cars. I connected the S line from the SFLP connector to the positive terminal on the battery and it now produces 15 volts all the time. The F line is connected through a 10amp fuse to switched 12volts. Will this over charge the battery and/or will it damage the alternator? Wheelman Quote Link to comment Share on other sites More sharing options...
Bartman Posted August 6, 2005 Share Posted August 6, 2005 Here's how my fan is wired. I have a Pilot 12V 30amp relay that is connected directly to my battery, the fan, ground, and a switch. The switch is also connected to ground (as well as to the relay) and gets power from my Painless auxillary fuse block. Now looking at this, I think it's all wrong! The fuse is protecting the switch and there is no fuse in the circuit to power the fan. I think I need to redo this the right way and use my PCM inputs instead of a switch to power both my high and low settings. I'll have to try and understand the drawings that have been posted to do this job correctly. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted August 6, 2005 Share Posted August 6, 2005 Bart, This is how I had mine wired: 12V from fuse block to relay, then from relay to fan (so this is the fused power supply to fan) Then I had an un-fused small wire (22 guage) from 12V power to toggle switch, then same size/color wire from toggle switch to switch terminal on the relay. Then the 4th post (other side of the switch portion) of the relay to ground. I used regular automotive grade relays. If you run to the JY, you can pull them all day long and walk out with a pocket full of them....payment optional Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted August 7, 2005 Author Share Posted August 7, 2005 The fuse is protecting the switch and there is no fuse in the circuit to power the fan. The only difference between your wiring set-up and mine is that I have the 60 amp fuse between the battery and relay power-in wire. I did not want to share any voltage with the wiring harness thus my direct contact with the battery. I heard that the more electrical accessories are powered separate from the harness by the battery, the more efficient they are and the harness becomes more efficient for the remaining items connected to it. I'm wondering if Tim240z has the right idea or if he is getting less amperage to his fan and it can handle the smaller fuse. But then he is not having problems. Hanns Quote Link to comment Share on other sites More sharing options...
pparaska Posted August 7, 2005 Share Posted August 7, 2005 It's a good idea to put a diode (like a 1N5408 ) http://www.fordmuscle.com/archives/2003/02/electricfan/index.shtml across the fan winding. You'd need two for the two speed fan. What it does is short out the back emf from the fan after the relay is de-energized, and keeps the contacts from arcing due to this back emf. If the wiring is too small in the total fan power circuit (like running it from the harness like Tim has) then you get less voltage at the fan due to the wiring acting like a resistor. Electric DC motors tend to draw less current when run below their designed voltage. http://www.gizmology.net/motors.htm That could be one reason that Tim's 20A fuse hasn't blown. I used a 60 maxi-fuse for my Mustang GT fan (I believe it uses the same motor as the Tuarus fan). That's the size fuse that the Mustang GT uses on the fan, so I just went with that. I measured 35 amp draw on high speed (didn't measure startup), with a 12.6 Volt battery. No doubt it probably draws more than 35 amps when running at 14V (alternator output voltage). Quote Link to comment Share on other sites More sharing options...
jack46 Posted August 7, 2005 Share Posted August 7, 2005 EVERY connection adds resistance. Resistance results in voltage drops. E = IR from ohms law. You want battery voltage applied to fan, so you want to minimize voltage losses. I always connect HIGH current devices from alternator, or battery through fuse, then relay, and finally the load. The low current side can be powered from almost any circuit. The relay will operate fine with less voltage since lower voltage mainly affects the time it takes to close. Then holding current is much smaller. I used dual 10 gauge wire to feed power to the fuses. I had my relays out front, but will move them inside and probably use two relays on high fan side. I also used this voltage to feed my headlights and used the old wire to power a relay. Thats why I had it up front. I had some problems with rain so I will relocate all relays inside of car, and might as well add second 30 amp relay for the fan high circuit. Starting current on any motor is always extremely high. PS and yes I also have a diode to minimize back emf. The relays I bought have them in the wiring connector I bought with them. Quote Link to comment Share on other sites More sharing options...
pparaska Posted August 7, 2005 Share Posted August 7, 2005 Jack, Are the diodes that relays and/or the sockets sometimes have in them large enough to survive long with the large back emf this fan motor puts out on high? Aren't those diodes for something more akin to lamp loads and not long (time-wise - due to spin down of the fan) inductive loads? The 1N5408 (referenced in that article I linked) is a pretty hefty piece diode - 3A forward, 500A reverse. Quote Link to comment Share on other sites More sharing options...
jack46 Posted August 7, 2005 Share Posted August 7, 2005 I think it is safer to assume they are to small and add additional diodes. Extra diodes will simply be capable of flowing greater current. If the diodes are too small they will burn out. But it will continue to work so you won't know they failed. Diodes are cheap and when doing it why not make it more robust and unbreakable. PS in many instance the diodes are not used! The failure when diodes fail or are not used will usually cause the relay to weld and leave the fans on. Not my idea of good design and not what I do. So if there is a failure you pull the relay and replace it. I know many who don't fuse either ASSUMING the relay will act as a 30 amp fuse. It won't. The relay is NOT an effective fuse, and can allow a fire, because the relay could fail welded and with no fuse it will flow current until something melts. This is often after a fire has started. PPS A diode is a one way valve of sorts so tends to conduct when voltage is applied in a certain polarity. http://www.fairchildsemi.com/ds/1N/1N5400.pdf Reverse voltage according to the datasheet is 1000 volts, peak current is 200 amps so it is a fair choice, but I would put two in parallel or an even larger diode to be certain. I believe in overkill especially when cheap as in case of diodes and wire size. Quote Link to comment Share on other sites More sharing options...
pparaska Posted August 7, 2005 Share Posted August 7, 2005 Agreed on the "cheap insurance is worth much" ideas . I need to upgrade my wiring to add those diodes. If I were to do this over, I'd use a 70 amp VF7 relay instead of two 30A VF4s in parallel. I have some now of the VF7s now, but unfortunately, they don't seem to make a chassis mountable socket like they have for the VF4. Quote Link to comment Share on other sites More sharing options...
Guest SupraGuy Posted August 7, 2005 Share Posted August 7, 2005 Turbo Meister, you got any video of that z tearing up the pavement. What a ruthless combo man...I am blown away! Quote Link to comment Share on other sites More sharing options...
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