Fan frustration!

[BLKMGK]

Okay, I've got a Cobra fan housing and what I was told was a Cobra fan motor from a wrecking yard. The motor has three prongs on it and looks liek every other Cobra fan motor I've seen so I believe this is correct. I have it wired such that the top prong is gorunded and I have relays going to the other two prongs switching 12 volts. I have setup my relays such that if I manually trigger one of them power to the other is cut off The only potential downside I see is that a failure in one of them might render the second inoperative (ahem). I have verified their operation with a volt meter and it works as I intended.

 

So, I needed to now figure out which prong was hi-speed and which was low. I had been told that running the fan on high all of the time could cause it to burn up - this happened to a friend (hence my getting the housing!). I put a jumper from the wire that I intended to use a thermo switch to hot and the fan cranked up - cool! I then flipped the manual switch in the cokpit (heh, avoided the censor) expecting to see the fan speed up or slow down - nothing changed!

 

Puzzled I played with the wires in various configurations on the fan using just one hot wire. I found a way to short them and I found a way to run the fan backwards just fine. However nothing I do seems to activate any sort of "hi-speed" operation. Desperate I ran juice to BOTH of the wires feeding the fan as this was how the wiring assembly that had been made fo rme was originally wired - again nothing changed?!

 

Have I missed something here? I'm not actually worried abut cooling since the fan blows up oen heck of a storm but darn it I want a low and hi-speed and I do NOT want to burn this motor up! I know from my friend's experience that it won't burn up super fast but this IS a junkyard motor so there's no telling. How has everyone else wired up the Taurus motors? Any troubles? Could this motor just be goofy?

 

Suggestions appreciated. At this point I may just not worry about it and enjoy the fact that I've got a manual option if I want it.

 

Would you believe that when the fan is on and the hood off that I can feel a slight breeze at the BACK bumper of the car? It sucks paper up against the radiator easily and I've got a good 1/4inch gap between the radiator and the fan housing - it's NOT sealed. Nice fan Pete, how hard would it be to wire up something to sort of delay time the fan turn off if I wanted? Sort of a cheap turbo timer?

[pparaska]

A few comments.

 

My car is STILL in paint jail (but it got painted Monday night!) so I can't really research this on my car.

... Anyway, I'm prett sure that the ground and high speed winding terminals are on the ends of the connector, and the low speed winding terminal is in the middle. Try testing for continuity between the fan motor housing or shaft and one of the outside terminals on the connector to see if that can tell you which outside one is ground. Use the ohms scale, since the winding resistance will read in the single digits most likely - you want to see Zero ohms to confirm which terminal is ground.

 

Another way is to use the outside terminals and hook it both ways - the way the pulls air through the radiator will tell you which should be ground.

 

Also, without 14V, the fan will seem to be slow, even on high speed. A few people that came to see my car before the engine ran thought that the GT stang fan was wimpy. Start the car, get 14V to the fan's high speed winding and you'll see what I mean. You think it's blowing now, just wait. Don't be surprised if your alternator belt squeals when the fan is on high with the engine idling! It pulls 35 Amps at 12.5 volts on high!

 

Anyway, once you find which is ground, 12V to the center terminal should give a lower speed.

 

BTW, the way the Mustang 4.6L cars work is to have the fan come on low speed at 221F coolant temp, and go off at 200F. If the A/C is on and the engine is above 221F the high speed comes on.

 

Remember to not run voltage to both the high and low speed windings at the same time.

 

As for a delay off circuit, there are delay on and delay off relays available through industrial electrical supply houses. Pricey though. It could also be done with an RC (resistor-capacitor) circuit with a relay, or a 555 timer and a small relay. I used the RC/relay circuit to give my fuel pump voltage while the engine was cranking.

[Guest Anonymous]

I seem to remember the Taurus having a three prong plug with the center lower than the two poles. I thought the lower (center) was a ground and the other two, low and high. I won't refute high burning out if left on all the time, but I'd have to wonder why if a car was in hot climates (Arizona (or even Sac today, 108 and humid) 100 degs + in shade...)all the time why that would be the case, since its likely it would be on high all the time. Time will tell, I do plan to put mine on some sort of circuitry, but I've got about 450 miles on mine with high only and it still blows a hurricane under there. Knock on wood (gives the Lone's melon a thump..).

 

Good luck with it,

 

Lone

[BLKMGK]

I'm pretty sure that I've determined that the top pin on this motor is ground. If I hook it anywhere else and get the motor going (one pin will always short straight through too if I move it from the top) it spins backwards so I think I've got ground right at least.

 

If anyone calls this fan "slow" I'll laugh at them. Even with just a bit over 12 volts at the fan it really blows alot! I have to weight down papers I have on the cowl to keep them from flapping around. If I can get a higher speed out of it I'll be VERY happy. Just wanted to kind of verify my thinking with how this puppy worked. I thought MAYBE having juice to two windings would give high speed after nothing else worked but then again maybe not. Hot to two poles at once just didn't seem righ tand Pete you had warned me about that before - hence my hassle with the solenoids. Luckily I noticed that these solenoids had a pin that was switched OFF when the relay kicked in. I ran that as the SUPPLY to the relay that will be running the thermo switch. Now when the first relay kicks on manually it also turns OFF juice to the second thermo switched relay

 

One thing does occur to me though... it's possible this motor is from a Cobra that had had the heat fix done to it. I think it was 96 or 97 that Ford had BIG problems with cooling Cobras in hotter climates. The motor is simply so big heat can't get through he bay and escape out. Even some of the Ford videos that were released showing desert driving had snippets in them where people spotted elavated engine temps. Eventually Ford relented and had a recall for this problem - I'm wondering if perhaps part of that "fix" was to install motors that were high speed all of the time regardless of temp?

 

As for my comment about them burning out. That was due simply to having a friend fry his. He had run it for at least a year so it obviously wasn't a quick thing. That truck (Lightning) was a daily driver so it certainly saw plenty of fan use in traffic. (shrug) Going on his experience I simply wanted to run low as "normal" and high when I manually clicked on the switch...

 

I believe a delayed "off" for when the car is parked would be a nice option. Not a big deal right now but I'll try to look into it. I'm also really wanting one of those delayed dome light modules Street rod places have them but they're not super cheap Any idea how hard it would be to retrofit an OEM piece? I have no idea how the OEM's have implemented that feature but I think it's really cool

[Guest Locutus]

Some Ford fans just die. The one in my mustang caught fire, and one in my mystique just quit one day. The mystique fan was covered in a recall, but i replaced it a week before we got the letter. Ford refused to reimburse me but thats another story. I think your friends fan probably just died, regardless of constant high speed use or not.

 

Mike