bschiltz Posted May 19, 2007 Share Posted May 19, 2007 One more question, where can you get the high speed switch? Would this one work? http://cgi.ebay.com/ebaymotors/Radiator-Fan-Switch-Ford-Escort-Tempo-EXP-Topaz-Lynx_W0QQcmdZViewItemQQcategoryZ33602QQihZ020QQitemZ300052521452QQrdZ1QQsspagenameZWD1V Would I be better off going to a junk yard? What about this if you set the low speed off temp lower? http://store.summitracing.com/partdetail.asp?autofilter=1&part=HYP%2D4028&N=700+115&autoview=sku Quote Link to comment Share on other sites More sharing options...
bschiltz Posted May 20, 2007 Share Posted May 20, 2007 New idea... What if you used these two controlers? http://store.summitracing.com/partdetail.asp?part=BCI-75029 http://store.summitracing.com/partdetail.asp?part=HYP-4028 Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 20, 2007 Share Posted May 20, 2007 New idea... What if you used these two controlers?http://store.summitracing.com/partdetail.asp?part=BCI-75029 http://store.summitracing.com/partdetail.asp?part=HYP-4028 I like it. I had thought of doing that years ago, a lower temp switch for low speed and a higher temp one for high speed. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted May 20, 2007 Share Posted May 20, 2007 I don't see why those wouldn't work. I mean they connect the two terminals at a certain temperature. I would run a ground through the switch as opposed to running 12v (you probably already know that). Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 20, 2007 Share Posted May 20, 2007 Woah. Those switches can't handle the amperages of the fan. You need a relay circuit that will turn the fans off and on. And they need to control the two speeds exclusively. Meaning when the higher temp switch sends the signal to the high speed relay, you need to make sure the low speed relay is turned off, so that the low speed wire to the fan is not sending current to the low speed winding in the fan motor. That's what this thread is all about. Make sure you go back and read about the circuits for this. Quote Link to comment Share on other sites More sharing options...
bschiltz Posted May 20, 2007 Share Posted May 20, 2007 Woah. Those switches can't handle the amperages of the fan. You need a relay circuit that will turn the fans off and on. And they need to control the two speeds exclusively. Meaning when the higher temp switch sends the signal to the high speed relay, you need to make sure the low speed relay is turned off, so that the low speed wire to the fan is not sending current to the low speed winding in the fan motor. That's what this thread is all about. Make sure you go back and read about the circuits for this. You mean don't use only the switches to control the fan, right? I think that's what 280zwitha383 was talking about. I was thinking using those switches to trigger the relays like Larry's setup, just replacing the switch from the ford tempo and the adjustable one. That would work, correct? Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 21, 2007 Share Posted May 21, 2007 Yes, that would work. Sorry for my confusion. Quote Link to comment Share on other sites More sharing options...
waynekarnes Posted May 21, 2007 Share Posted May 21, 2007 Pete, that's how i have the two speed taurus fan wired in the scarab. 185 fan sw for low speed. 203 fan sw for high speed. slightly modified Cozy Cole's set up. the 185 degree fan switch is easy to find. the 203 is export 1995 corvette switch. i don't have any manual switches. using Cozy's set up with the relays, if temps are high enough, when the 203 sw goes to ground, path to ground to the 165 is interupted. removes power to low speed fan, other relay closes, supplies ground and power to the high speed fan motor. set up works great. i'm using the JTR raditor and mount. a short nascar high volume aluminum water pump, high flow 185 degree thermostat. 104 amp alternator. coolant with water wetter. on 101 degree day, let car idle in driveway for over half an hour. using a meat thermometer in the radiator vanes, temps never got above 190 degrees. to test the 203 degree wiring, i shorted the connection to ground. the low speed shut off, high speed came on. knew my wiring was good. after engine had been idling for almost 45 minutes i used a sheet of card board to block off the radiator ( remember was 101 degrees in my driveway ). took little over 8 minutes for the temps to go up high enough for the 203 sw to go to ground. low speed went off, high speed came on. i removed the card board. took less than 4 mins for coolant temps to drop back down to where the high speed shut off and the low speed came on. using the fan switches and Cozy's relay set up is the way to go. fully automatic. wayne Quote Link to comment Share on other sites More sharing options...
bschiltz Posted May 21, 2007 Share Posted May 21, 2007 Yes, that would work. Sorry for my confusion. Cool, thanks! Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted May 21, 2007 Share Posted May 21, 2007 You mean don't use only the switches to control the fan, right? I think that's what 280zwitha383 was talking about. I was thinking using those switches to trigger the relays like Larry's setup, just replacing the switch from the ford tempo and the adjustable one. That would work, correct? Yeah, that's what I was thinking but not what I was saying. So... the higher amp relay is what gives you the "high speed" right? Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 21, 2007 Share Posted May 21, 2007 I'm not sure what you mean by the higher amp relay giving the higher speed. The higher speed comes from giving sufficient voltage and current to the high speed winding in the motor on the fan. The high amperage rated relay just allows a sufficient amount of current to get to the high speed winding in the motor. Hope that helps. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted May 21, 2007 Share Posted May 21, 2007 I must have a different fan then what you guys are talking about. The fan that I have is out of a 98 Taurus I think and about two years ago I opened it up and even though it has 3 terminals, two of them are basically connected (one for ground and two for power). That's what my hang up is I think. I guess with the one I have the speeds were controlled by different relays/current. I do have one LARGE fan from a V6? Mustang that may or may not be like the one that you have. Maybe I'll give it a shot if I'm still borderline cooling this summer. I guess that's why noone has answered my question because they have no idea what I'm talking about Quote Link to comment Share on other sites More sharing options...
bschiltz Posted May 21, 2007 Share Posted May 21, 2007 Hmmm... Well I guess that makes sense. Both the wires go to the same place because they drive the same motor. One is just routed through a higher amp circuit, which gives the fan the high speed. I guess it's like you could take the interstate or a two lane highway. They both go to the same place, but one can carry more cars. Edit: I just wanted to say I didn't want to sound patronizing, it wasn't intended. Quote Link to comment Share on other sites More sharing options...
bschiltz Posted May 29, 2007 Share Posted May 29, 2007 Well I bought the two switches I posted above and wired everything up this weekend. I ran the motor for 5-10 minutes (open headers, my neighbors love me ) and the low speed triggered just fine. I didn't get it hot enough to trigger the high speed switch, but I did check to make sure it worked. I took the lead from the high speed and touched it to the post on the low speed switch which should throw the aux relay shutting off the low speed and opening the high, which it did. I'll get pics in a while. Quote Link to comment Share on other sites More sharing options...
bschiltz Posted July 28, 2007 Share Posted July 28, 2007 Just wanted to say I've been running the set up I was talking about (with the two switches I linked) for ~100 miles now and everything is working great. I had to change the T-stat from 195 to 180, but other than that it hasn't overheated at all. I'm working on a diagram of my wiring, I'll post it when I'm done. Quote Link to comment Share on other sites More sharing options...
bschiltz Posted August 7, 2007 Share Posted August 7, 2007 Here's the diagram. It's basically the same as the two Larry posted, just all in one diagram Quote Link to comment Share on other sites More sharing options...
Guest 73LT1Z Posted September 22, 2007 Share Posted September 22, 2007 I read through this thread & one on LS1tech, and came up with this "Hybrid" diagram for those using the single two speed fan and wanting to control it with the PCM: This is for a 1998 PCM. 1999+ would use terminals C1-42 for low speed and C2-33 for high speed. I think this should work, but I've been studying wiring diagrams all morning, so another few sets of eyes on it would help . Quote Link to comment Share on other sites More sharing options...
Guest deadzoneman Posted October 3, 2007 Share Posted October 3, 2007 I have a 78 chevy 4x4 with a taurus 3.8 fan i hooked it straight to the ignition switch from a toggle switch and a 30 amp fuse between the fan and the fuse box i noticed every 4 days or so it blows my 30 amp fuse is there something i did wrong i want it hooked to a toggle for now then i will wire it the right way with a controller someone told me i need a 75 amp relay in replace of the fuse is that true and can someone send me a basic diagram that explains it in detail with a toggle switch and a relay thanks or call me 360-513-3767 Quote Link to comment Share on other sites More sharing options...
Guest 73LT1Z Posted October 3, 2007 Share Posted October 3, 2007 I have a 78 chevy 4x4 with a Taurus 3.8 fan. I hooked it straight to the ignition switch from a toggle switch and a 30 amp fuse between the fan and the fuse box. I noticed every 4 days or so it blows my 30 amp fuse. Is there something I did wrong? I want it hooked to a toggle for now then I will wire it the right way with a controller. Someone told me I need a 75 amp relay in replace of the fuse. Is that true and can someone send me a basic diagram that explains it in detail with a toggle switch and a relay or call me 360-513-3767? Thanks You did not say what size wires you are running. You need at least a 10 gauge going to the relay and fan for the supply side. A normal 30 amp fuse is marginal as you have found out. These fans spike a load when they startup, which is what often blows the fuses. Also, you want direct power before the fan's fuse holder, so hooking it into an existing fuse panel will limit the power you can draw. Try hooking the fuse holder to the battery + terminal or the smaller wire with the battery cable- usually goes to the back of the alternator. Fuses and relays do different things. Fuses blow to prevent short circuits and things like melted wires and battery explosions. Relays allow small diameter wires to switch loads (turn things on) beyond their capacity. You need both in this situation. If you are not running a relay at all now, I'm surprised your fuse is not blowing each time the fan turns on. What I would suggest is to get the 75 amp Bosch relay (Waytek part # 75552), and run at least 10 gauge wire to it from an inline fuse holder. You can trigger the relay from your ignition switch with no problem. You need to have a fuse of the proper capacity, so I would go with a 40 amp maxi fuse (see below). The nice thing about the Bosch relay is it can accept HD ring terminals, not just the blade terminals like the regular 30/40 amp relays. Everything you need can be ordered here at decent prices: http://www.waytekwire.com/ You are looking at about $20 for the relay, $8 for the fuse holder (have to buy 2 since they have a $5 minimum per part limit), $5 for a 40A fuse set, and probably $10 for some wiring connectors unless you already have some or can pick some up locally. Here is a PDF page showing a maxi fuse holder, it has 6 gauge wires and can carry up to 60 amps: http://order.waytekwire.com/IMAGES/M37/catalog/219_077.PDF For general relay wiring, go to http://www.the12volt.com/relays/relays.asp What you want to do is hook the wire from the fan to terminal 30, the wire from the fuse to terminal 87, the wire from the ignition to terminal 85 and ground terminal 86. You will know it is wired right when you turn on the ignition and hear the relay click. The 75A one is loud. Also, you need to be sure the fan is properly grounded. You should have the same gauge wire connected to the ground side as you do the supply side, like a 10 gauge, and it has to go to a good ground point like the frame or core support. If poorly grounded, this puts extra load on the supply (+) side since the power is coming in and not going through fast enough. EDIT Got your email, I have drawn and attached a diagram that illustrates the above wiring. Quote Link to comment Share on other sites More sharing options...
Guest deadzoneman Posted October 4, 2007 Share Posted October 4, 2007 hi everyone im having a hard time understanding the way to hook up a relay to my fan ok i have ford taurus fan 3.8 i have a wire coming from my fuse box with key switch power coming out of the fire wall with 30 amp fuse spaced between fuse box and fan then it goes straight to the fan with fan grounded now sometimes when i start my truck my fuse blows every 3 days or so so i was told use a 75 amp relay now would i hook up the relay in replace of the fuse i have or also keep the fuse also now what kind of relay is the best and can someone make a better diagram that explains better to a dummy please email me at die_hard_man2005@yahoo.com or call me 360-513-3767 mike thanks Quote Link to comment Share on other sites More sharing options...
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