Fan Wiring Help needed

[g-money]

I finally found a junk yard fan that will fit in between the serpentine setup and the radiator without modifying the core support so I want to give it a try. It it sucks and doesn't keep it cool I can easily yank it out and go mechanical.

The fan has 4 wires coming out of it. 2 power and 2 ground. It is basically a two speed fan from the test I have done. If I put power to one wire and either ground it low speed then if I put 12 volts to the other wire and either ground it is a higher speed. The other thing is if I put power to both power wires I get a really high speed, which I figure is not good for the motor long term but might be OK for short bursts to get cool in an emergency (if someone thinks this is bad logic please let me know.

I want to wire the set up so that it is off if the temp is lower than 190, then turns on the high speed at 190 or above. I don't want to use the lower speed since It seems too low to do any good.

That part is easy to wire but I also want a manual switch that I can activate to give 12v to both power wires so the super high speed comes on if needed.

I want to wire it as in the picture below but I am not sure the relays work as I need them. If I active the high/low relay and energize post 85 will I get power to both 87 and 87a? if not is there a relay that does this? I am confusing myself by having to have 12v to both power sources.

Thanks for any help

Galen

 

[getfuzzy]

check out Painless web site they have wiring instructions look at 30115 it the one I'm using for my mark 8 fan

 

[Viperwolf1]

87 and 87a do not have continuity to 30 at the same time. When one is on the other is off.

 

[g-money]

So is there a relay that does energize 87 and 87a? I have looked at the painless set up but I need to have one wire energized when the temp switch kicks in and have both wires energized when I activate the switch. The second part is what is giving me a hard time.

Galen

 

[Viperwolf1]

If you use a 3 throw switch you can make it work with those two relays. One throw for the low speed, one for high and one for both. You would need to wire pin 87 of the relays directly to the fan, one to high and one to low.

 

[lonesouth]

this is a differnt way to approach this circuit. I prefer to use a ground as the signal to relays. It is both easier, ground the input side of the switch and run the output to the relay ground, and safer, fewer wires carrying voltage to get pinched and cause a short (personal opinion, may not actually be safer).

The fan control is now Off/Auto Low/Auot High. When OFF, the output from the TEMP SWITCH is grounded, preventing the power relay from switching the power output.

When LOW, the TEMP SWITCH controls power to the HIGH/LOW RELAY which will be off because of the open on pin 86.

When HIGH, the TEMP SWITCH controls power to the HIGH/LOW RELAY which will be on because of the ground on pin 86.

The TURBO SWITCH will require running a power wire from the POWER RELAY pin 87. The output of the TURBO SWITCH will control the TURBO RELAY. For the TURBO RELAY to work, the FAN SWITCH must be on HIGH. The TURBO RELAY adds power to the LOW INPUT of the fan. This is a momentary switch due to your concern about long term use of turbo having a detrimental effect on the fan.

There are better ways to design this circuit, but this is first crack at what should be a functional circuit. Note that the 150A POWER RELAY does not have to be 150A, rather it should be 10% higher than combined current draw of BOTH HIGH AND LOW of the fan.

 

[g-money]

Lonesouth, Viper, Thanks for the help and the drawing. I see how your set up will work but it's not exactly what I want to do. I may have not been clear about it (I am confusing myself so I am not surprised.) I want to have it set up so I use one switch and in one position (auto) is uses the temp switch to turn on the high side of the fan when the temp rises above a certain temp. I figure this switch I will just leave on most of the time.

Then I want the other side of the switch to operate the "turbo" side of the fan which is actually both positive wires hooked together. I figure I would only use this option for short periods maybe sitting in traffic on a hot day.

I don't want to you the low option of the fan, it's just too low. I only want high and turbo.

If it's possible I'd like to have each wire from the fan hooked to one relay. On auto mode it energizes one relay (via the temp switch) and on Turbo mode it energizes both relays.

Does this make sense?
I really appreciate the help.

 

[Viperwolf1]

Lonesouth, Viper, Thanks for the help and the drawing. I see how your set up will work but it's not exactly what I want to do. I may have not been clear about it (I am confusing myself so I am not surprised.) I want to have it set up so I use one switch and in one position (auto) is uses the temp switch to turn on the high side of the fan when the temp rises above a certain temp. I figure this switch I will just leave on most of the time.

Then I want the other side of the switch to operate the "turbo" side of the fan which is actually both positive wires hooked together. I figure I would only use this option for short periods maybe sitting in traffic on a hot day.

I don't want to you the low option of the fan, it's just too low. I only want high and turbo.

If it's possible I'd like to have each wire from the fan hooked to one relay. On auto mode it energizes one relay (via the temp switch) and on Turbo mode it energizes both relays.

Does this make sense?
I really appreciate the help.

You need a diode.

 

[lonesouth]

agreed. easiest setup. Zener diode right? not sure on the value though...

 

[g-money]

Well I just looked up what a diode was and is seem like that is the trick. What I learned is it lets current pass in one direction only.

Any idea what kind I might need. I figure I can pick one up at radio shack but if you have more specifics on which one I may need it would be a big help.

Thanks a bunch for all the help. I REALLY appreciate it.

Galen

 

[Viperwolf1]

Do not use a zener diode. Use something like a 1N4004. Zener diodes will conduct in either direction depending on the voltage.

 

[lonesouth]

learning is fun, thanks for the correction...sounds like a zener might give you some odd behavior

 

[Viperwolf1]

It has it's uses. It's good for voltage regulation.

 

[oleguy74]

thats what a zener diode does.voltage reg.

 

[g-money]

You guys ROCK! Thanks a bunch. I love this list, I learn so much from it. I now know what a Diode is and will actually be using one.

Galen

 

[samamarshall]

Jeez...this doesn't make sense to me at all, but I'm def saving this thread for when I do install an elect. fan. I'll decipher it then ;D , or just call my elect engineer buddy over