I know I posted this in the performance mod forum but I get more replies this way.

I finally found the link about the FD fan mod. I am doing this next. I want to understand it a bit further and make sure that I operate this mod properly. Please don't think of these as dumb questions. When it comes to my 3rd gen, I have to be 101% because it is so fragile and expensive to replace engines, turbos, etc....

- I know you can trigger the radiator fans when you turn the headlights on and when you turn the ac on. I also know that you can lower temps by turning the heater on but can you turn the mod fan switch while you are driving? When I am in the highway, the car temps are really low - around 160/180 F. On a stop and go in the city, it gets really hot - around 210/230 F. I usually turn on the heater to blow out the hot air.

- Can you or do you switch it on when the car is off? I have read at KDRotary's site that it can run up to 10 minutes after the car has been turned off.

- If you turn it on while the car is off, after ten minutes will the fans shut itself off?

Anything else you think I left out, please speculate.
Thanks all...I don't know what I would do without this forum.

Laters,
Jason

 

Its okay to turn it on while driving. I turn mine on when I stop at lights or I am going slow, I figure no use having them on when I'm going at least 25. Be careful though, when I wired mine in I had to cut one of the wires going to the switch because my fans were acting weird, now with the switch on I get low speed and if I turn the switch on when the fans are running I get one speed higher.

 

The fan has three speeds.

Low speed is not used

Medium speed is turned on by either the AC thermoswitch, the ecu or the diagnostics wire.

High speed is turned on by the water thermoswitch (engine temp).

The standard fan mod is to ground the diag wire and this will keep the fan on med speed as long as the ignition key is on. When the key is turned off, the timer in the ecu will keep the fan on medium speed for two minuts not ten.
The standard fan mod works well for cooling the car after shutoff. But on a hot summer afternoon in Georgia it really doesn't do much.
When you stop in traffic the high speed fan is still being controlled by the water thermoswitch (220F)

By using a seperate variable temperature fan switch to replace the water thermoswitch, you can do two things.

1. Adjust the temperature setting to turn on the high speed mode for better cooling at traffic stops. (mine is set at 190F, and it stays there even when it's 100F ambient) Just a word of caution, if it is set below 190 the engine will not reach proper operating temperature on a cool day.

2. Connect the master control line to a +12v source will keep the fan cranking at high speed after the engine shutoff untill the temperature has dropped below the preset limit (190F for me)

The standard fan mod is much simpler to do, but IMO insufficient if what you want to do is lowering the operating temp. If you want to go the second rout, let me know and I can give you more detailed how-to instructions.

 

Hey trex, I believe the low-speed fan comes on when the parking lights are turned on.