So I ditched the stock cooling fan when I did my engine swap. Im running 2 puller fans on a stand alone adjustable fan control unit. I know on the stock setup, the cooling fan was computer controlled. It would shut it off at like 40MPH, since the airflow being forced in from the speed was greater than the fan could pull, the fan wasnt doing any cooling and therefore wasnt needed at that point. Now with my stand alone fan control, its just a temp switch that activates a relay at whatever temp I set it at regardless of vehicle speed. I wanna know if anyone has a thought on how it could be wired in to shut the fan off at a certain speed. Is it possbile to wire something to read the raw VSS signal, and at a certain speed and above, trip a relay to shut off power to the fan control unit?

 

Sounds like a great idea. I'm in the same boat here - seperate fan controller. But I have no electronics knowledge or knowledge of the inner workings of the VSS.

But I do notice, at least in my car, that if I'm moving 40+ mph, that my system cools well enough (even on 90*+ days) where my fan doesn't stay engaged for long after those speeds are obtained anyway. (I have a led in the dash that lets me know when my fan is running).

 

I have my fans set to come on right at 180, so theyre pretty much on the whole time after the car warms up. I know the VSS uses a sine wave that varies pulses by speed, but I have no idea how to get something to read that signal and use it to trip a relay to cut power. Im not electrically dumb, but thats just a little out of my range of brain power.

 

I would try to wire up somthing that turns off when the TCC engages, I think it engages above 35 or 40? Mines easy, I have a TCC switch so highway speeds, TCC switch on, fan off.. they do have relays that kill power when you run power to it, its like the opposite of a normal fog light relay.

 

I don't see a point. If you're moving fast enough that there's enough airflow without the fan, then you'll be running cool enough that the fan will turn off anyway.

 

IDK some may not want the power draw? May not be much but it also keeps the contacts from wearing out faster. If its factory to shut off at 40 then there must be some pointless reason to this madness! lol

 

There won't be any power draw because the engine will be cool from the slipstream air, and the fan will be off already.

 

The TCC idea might work for auto setups, but I run a manual trans. And as stated, Ive got my fans set to come on at 180 (which means the off temp is lower than 180). Once the car is warmed up, it NEVER drops below that. So even at highway speeds, with the engine getting plenty of fresh cool air, the temp doesnt drop low enough to kill the fans. Hence why Id like some way for the vehicle speed to shut them off. Ive thought about wiring in a switch on the ground side of the fan control to kill them that way, but Id rather have my car do it for me

 

There was a post I seen in this post: https://www.thirdgen.org/forums/fabr...some-pics.html

The guy wired up a shift indicator light to show the number of gear he's in. The setup he made for the shifter can also be used to throw power to a cut off relay in 4th and 5th gear using contact switches! I thought that was pretty cool.

 

It would take a bit of creativity but it would be a solid piece of fabrication you could share on that post.

 

Based on the above pic - maybe just a single switch in the console that makes contact and trips a relay when you are in 6th gear.

180 is a bit low for fan to come on, I have mine set right at 200 for an on temp. I'd think you'd run a tad rich at a temp as low as 180. I mean hot is bad, but too cool isn't as efficient either.

 

Thats actually not a bad idea. The fan relay would only be cut off in 5th or 6th gear (gotta love double overdrive) so only at hightway speeds.

 

I had the fane set low because I was having an overheating issue. I havent lowered it since I fixed it.

 

Haa! Finally Im useful lol I came up with this wiring diagram for doing the relay:

The relay is normally on, meaning there is always power running thru it. Only when you put 12 volts thru the switch will it switch it off. Relays dont draw hardly any amperage too. Just make a cut in the +12v wire to the fans and hook it to a normally open relay (copper terminals usually), then take the same +12v source to the fans and put it on the switch side (steel terminals usually) and the ground side of the relay switch runs to the shifter tower, where you could have some kind of plate, possibly bolted using the existing bolts? and just have a flexible strike plate for 5th and 6th. When the shift handle hits the strike plates then it grounds the relay switch, makes it "click" and the normally open switch is now a closed switch, killing power to the fans while driving in 5th or 6th.

For automatic transmissions, the relay is wired exactly the same, but the switch is grounded straight to the body, and the switches power will come from the (I think its tan) +12v wire that powers Torque Converter Lockup.

Im gonna have to do this now (: Im looking for some electric cooling fans for my Z28, for now Ill have to use the stock engine powered fan

 

i also have an aftermarket controller for my 4th gen fans. its a flexalite controller.what i did was set it to come on just above 180 degrees. prolly about 190. so when i am in traffic the fans come on at 60%. then 100% if needed (never has). when i get on the freeway they never come on. now i dont have a/c either. but with the flexalite controller there are 2 provisions that are available. there are 2 wiring deals available for switches. 1-100% on and the other 100%off. so if you are goig down the freeway at around 55 to whatever and have a/c you could hit the off switch and they would never come on. but you have to remember to turn the switch back on.

 

Hmm I havent thought of that, I never had electric fans before! I assume better aftermarket fan controllers will have an option that turns them on for a/c power on, but still, the fans would be useless going over 50mph. But the fans going from 60% normal to 100% while the a/c is running is probably smart, not that a/c pump itself will overheat an engine its the condenser that will do it, since they get around 140 degrees! So instead of having cool 90 degree summer air cool the radiator you have air moving passed a 140 degree condenser haha! Most people dont realize this. Thats why Stock fans kick on faster with the a/c while youre city driving (not over 40-50mph)

 

BTW I ripped all my a/c components out (: I ride 2-65!

 

I run the exact same setup, 4th gen fans with the Flexalite controller, it is a great setup that does a fantastic job of keeping my 406 cool even on the hottest days. I don't have any a/c in the car yet, but I am sure it will do the job just fine. I have mine set to come on at 200* and will turn off at 190* which seems to be what the car and engine like.

 

My controller has a wire that runs to the AC clutch, so it overrides the temp switch and kicks both fans on when the AC is on. Having AC might make it a little more diffcult to wire in a normally on relay. Im going to go home and dome some deep thinking on this ans see what I can come up with.

 

when the a/c comes on they come on at 100%. now if you wired the fans up to be like the 4th gen original
a/c on not up to temp one fan comes on
a/c on up to temp both fans come on
up to temp both fans come on at around 60%

i have the diagram. do you have a/c

now what i did when i had this same controller on a truck was put a switch on the a/c signal wire to turn it off on the freeway.

 

Even if the fans are going at 100% I dont think that they can pull more air than whats being forced in by the wind speed going over 50mph highway speeds. The a/c would only over heat your car if you dont run a fan while cruising or idling.. well unless you have a bad radiator and the car overheats no matter what, especially a carbureted car thats running too lean!

 

well the fan may not pull the same air as the air coming in. but gm cant be wrong in over 100's of thousands of vehicles. trying to reinvent the wheel is pointless. and they still put out the same deal with fans now. a/c on fan on.

 

Would you run your radio while cruising down the highway, but leave the volume muted? I dont think turning off an electrical circuit that isnt serving any purpose is pointless. Yea it isnt a huge drain on the system, but why power a motor to spin a fan blade when the incoming air is going to spin that fan blade faster than the motor can? And like i said, I still hav my ac, and I would wire it up so that it operated the same way as the factory. Anytime the AC clutch is engaged, one fan is going to run.

This whole idea is to get the fans operating LIKE STOCK. Shuting off at high speeds and working off the temp switch like normal when in the city/not in 6th gear (or 5th gear or whatever criteria you wont to go with).

 

If you want it operating like stock, why do you have the fan turning on at 180?

 

yes i know this is for fords. but i used one of these controllers for a ford truck i used to own and one of his fans. didnt think about it till now. but the a/c sensor did work well. im sure he would sell just the sensor. check this link.

http://www.madenterprise.com/fan_control.htm

 

As stated above, I was having a problem with over heating. So I had the fan come on sooner and it kept me from getting over 230 in stop and go traffic in a Texas summer. I have since fixed the problem and just havent readjusted my fans. Besides I said I wanted it to function like stock, but i didnt say exactly like stock...

 

Unless the contact was constant through the 5-6 shift (a sidebar contact), the fan would come on and shut off between shifts.

 

Id just make the contact for 6th since sometimes I get into 5th on surface roads.

 

Exactly, but just for a second. A contact that runs parallel to 5 and 6th would be a great idea still.