Aux fan spec's and operation Questions

[infinity5]

Tell me if i'm right about this...

As i remember reading,
The auxilluary cooling fan operates under two conditions: a) the A/C is active, or b) the coolant temperature reaches a certain point, as determined by the coolant sensor mounted to the right side of the radiator.

Right?

Ok, now for my question. I know this is totally noob, but i seriously don't know anything about simple electrical systems.

There are three prongs on the aux fan power connector. And a resistor mounted to the fan. What purpose does this resistor serve, and if i wanted to operate the fan manually what power would i send to which pins?

I've got it out of the car and i'd like to test it before i try to repurpose it as my temporary primary cooling fan.

In that same vein, any suggestions on how i should wire the fan into the car if i'd like it to run more frequently/always.

[shogun]

I do not understand why you want to change a working system. It goes automatically at that speed what is needed. If you have it on all the time, it will cool too much.
Even the fan with the visco clucth you normally do not need when driving at highways with moderate speed, because there is enough wind which goes thru the radiator.

That is called a ballast resistor, a high-power low-value resistor in-line with the fan.
Its purpose is to give the fan 2 speeds, one high speed when the resistor is out of the circuit, and one low speed when the resistor is in the circuit. That is when there is also two thermal sensors attached to the radiator.

Brown wire (always brown) for ground.
The other two wires are one for the stage 1 speed, the other for stage 2 speed.

Pick one and apply 12V, you can tell if it works, it is pretty loud.

To check high fan speed, remove plug to temp sensor and bridge the 2 pins in the plug (with ignition switched on).

[infinity5]

I do not understand why you want to change a working system. It goes automatically at that speed what is needed. If you have it on all the time, it will cool too much.
Even the fan with the visco clucth you normally do not need when driving at highways with moderate speed, because there is enough wind which goes thru the radiator.

Thank you very much shogun.

The reason i'd like to change the system is becuase at the moment it doesnt not work- my viscous fan clutch is broken, my ac condensor is damaged, and the front end of my car has been crushed in. I also have no money, and i'm looking at the least expensive option to keep my car cool in the traffic we have here for as long as i can get by with it.

If it will turn on at appropriate temperatures then that's fine, i'll leave the electrical aspect alone, but i was under the impressive that it activated as a sort of ""last resort"" if your primary engine fan could not keep the temp's down. That seems like a poor way for it to operate if it is going to take over primary cooling of my engine.

[genphreak]

Why? The combination of a viscous fan clutch and thermos is the best you can have. Thermos are cheap but they are not reliable- and they do not offer enough granularity over the airflow. The viscous fan clutch allows constant coolant temperatures to be maintained which gives the cooling system, hoses, etc. extended service life and improves economy also.

The only way to replace the mechanical fan with any real outcome would be to a) overcool if you were wanting to ensure you don't cook a turbo motor for example, or b) install variable resistors to control fan-speeds and have a really well-engineered temperature monitoring system to control them which can maintain ideal combustion temperatures regardless of outside influences. That's a heck of a lot of re-work to do...

[shogun]

You can bridge the contacts with a simple clamp at the connector at the radiator, then it will always run at highest speed. (provided the relay for high speed is alright)
But as last resort to cool down the engine there is an easier method, which I use:
turn on the heater at highest temperature, set the blower fan for the heater at highest temperature. That brings the temp down.

[infinity5]

I agree, but i as i mentioned in my reply to shogun, the fan clutch has siezed and i do not have the ability at this specific moment to purchase a new clutch, and then drain the radiator, remove it(assuming that is still possible given the chassis damage) and take the fan off and change the clutch. Either way, the aux fan no longer fits on the automobile in its normal position, as the sheet metal above it crushed into it so as to restrict its movement

If i had the $5,000+ the body shop wanted to repair it, i'd be driving a bimmer with a brand new front end around town

Why? The combination of a viscous fan clutch and thermos is the best you can have.

[infinity5]

turn on the heater at highest temperature, set the blower fan for the heater at highest temperature. That brings the temp down.

That's a good tip. I'm sure i will find myself in a situation soon that i may take advantage of it.