Re-wire electric fan?

[KITT]

Has anyone re-wired the electric fan to a toggle switch? I thought this may be handy at the track for cooling purposes with the electric waterpump. thanks Brett

 

[matt06]

just saw this on jpc's website, figured it may help if you do it

http://store.jpcracing.com/Painless-Fan-Relay-Universal-70-Amp-Fan-Relay-KIt-_p_1286.html

 

[AlbertD]

I did mine, works great in the pits with the electric w/p on. Cools down literally in less than 10 minutes. Great mod!!

Here is a link that will help you get the switch started...
http://s197forum.com/forum/showthread.php?t=7016&highlight=fan

I did this about two years ago so I don't remember exactly how to do it if not I would just tell you. I do remember however that I tapped into the relay for the high speed fan in the fusebox.

 

[TexasBlownV8]

Just did mine a couple months ago, like Bad281, wired in so I could turn on the electric water pump and/or cooling fan whenever I want. And at the track, it is indeed great to have and really cools down the car fast. Plus, with the fan, I can turn it on while waiting for my burnout, keeping the temps down as well.

I have it set up so the low-speed side of the fan comes on, and it's plenty strong enough to cool things down.

The question you have to ask: do you want to be able to turn the fan on with the key off or only when the key is on? It makes a difference for wiring it up.
Also, do you want the high speed or low speed wired up? There's two separate circuits, but they come together at the fan.

Since you're asking about cooling at the track, I'm assuming you're interested in setting it up for the fan running with the key off.

If you look at the relay wiring diagram in the BEC, there's a master relay that is energized when the key is on, and this relay feeds the power to both the low and high speed relays' coils. The PCM energizes the specific relay by grounding (inside the PCM) the other side of the relay coil, thus energizing either the high or low speed relay and sending power to the fan plug.

The easiest way to wire in a switch is with a separate relay, set it up so when the relay is activated, the relay closes and feeds power to one side of the fan (high or low speed).
You wire in a switch of course to energize this separate relay.

The high-speed circuit is fused with a 40 amp fuse in the BEC, and so is the low speed, but the low speed can get by with a 30A fuse. You can tape a large enough wire (I used 10 ga. on the high speed and 12 on the low speed), and tap into one of the green-strioed wires going to the fan plug. The green/violet is the high-speed. One of the wires is not used and not connected to anything, so you could probably even splice into that one.

Run that wire to pin 30 of a separate relay, then from pin 87 of that relay, run a wire to a fuse (30 or 40 amp) and to battery power. Run a smaller wire after the fuse to pin 85 to the relay, then run a wire from pin 86 of the relay to a switch, then on the other side of the switch to ground.

The way I wired mine up was a little different, but I used two relays, one for switching the high speed circuit, one for the low, and tied into two unused BEC fuse locations, and set up so depending where I put a fuse in the BEC, I use either the low or high speed circuit. And when my switch is on, the stock fan circuit (both high and low) is completely disconnected, and instead, power is fed through one of my relays to the fan.

The water pump was easier to do something similar with, but I have it wired up so it too gets relayed power when the key is on, or using a switch, I energize the relay myself. I use a diode on the switch side so as to not also turn on other key-on circuits with my switch.

A wiring diagram pic would probably make sense, and I have one drawn out on a large easel sheet of paper, but no pic is taken of it yet.

...did a little wiring re-route and engine bay cleanup..moved the wires to exit out the BEC on the engine side, and added 2 relays inside the bec in the convertible top location and 3 relays outside below the bec, 2 for the fan as mentioned above, and 1 for the electric water pump.
http://i224.photobucket.com/albums/dd92/texmike_photos/100_0390-s.jpg
http://i224.photobucket.com/albums/dd92/texmike_photos/100_0393-s.jpg
..engine siring harness cleaned up and rerouted
http://i224.photobucket.com/albums/dd92/texmike_photos/100_0387-s.jpg

 

[94tbird]

Just did mine a couple months ago, like Bad281, wired in so I could turn on the electric water pump and/or cooling fan whenever I want. And at the track, it is indeed great to have and really cools down the car fast. Plus, with the fan, I can turn it on while waiting for my burnout, keeping the temps down as well.

I have it set up so the low-speed side of the fan comes on, and it's plenty strong enough to cool things down.

The question you have to ask: do you want to be able to turn the fan on with the key off or only when the key is on? It makes a difference for wiring it up.
Also, do you want the high speed or low speed wired up? There's two separate circuits, but they come together at the fan.

Since you're asking about cooling at the track, I'm assuming you're interested in setting it up for the fan running with the key off.

If you look at the relay wiring diagram in the BEC, there's a master relay that is energized when the key is on, and this relay feeds the power to both the low and high speed relays' coils. The PCM energizes the specific relay by grounding (inside the PCM) the other side of the relay coil, thus energizing either the high or low speed relay and sending power to the fan plug.

The easiest way to wire in a switch is with a separate relay, set it up so when the relay is activated, the relay closes and feeds power to one side of the fan (high or low speed).
You wire in a switch of course to energize this separate relay.

The high-speed circuit is fused with a 40 amp fuse in the BEC, and so is the low speed, but the low speed can get by with a 30A fuse. You can tape a large enough wire (I used 10 ga. on the high speed and 12 on the low speed), and tap into one of the green-strioed wires going to the fan plug. The green/violet is the high-speed. One of the wires is not used and not connected to anything, so you could probably even splice into that one.

Run that wire to pin 30 of a separate relay, then from pin 87 of that relay, run a wire to a fuse (30 or 40 amp) and to battery power. Run a smaller wire after the fuse to pin 85 to the relay, then run a wire from pin 86 of the relay to a switch, then on the other side of the switch to ground.

The way I wired mine up was a little different, but I used two relays, one for switching the high speed circuit, one for the low, and tied into two unused BEC fuse locations, and set up so depending where I put a fuse in the BEC, I use either the low or high speed circuit. And when my switch is on, the stock fan circuit (both high and low) is completely disconnected, and instead, power is fed through one of my relays to the fan.

The water pump was easier to do something similar with, but I have it wired up so it too gets relayed power when the key is on, or using a switch, I energize the relay myself. I use a diode on the switch side so as to not also turn on other key-on circuits with my switch.

A wiring diagram pic would probably make sense, and I have one drawn out on a large easel sheet of paper, but no pic is taken of it yet.

...did a little wiring re-route and engine bay cleanup..moved the wires to exit out the BEC on the engine side, and added 2 relays inside the bec in the convertible top location and 3 relays outside below the bec, 2 for the fan as mentioned above, and 1 for the electric water pump.
http://i224.photobucket.com/albums/dd92/texmike_photos/100_0390-s.jpg
http://i224.photobucket.com/albums/dd92/texmike_photos/100_0393-s.jpg
..engine siring harness cleaned up and rerouted
http://i224.photobucket.com/albums/dd92/texmike_photos/100_0387-s.jpg

You should change it to the high speed fan. Your using the same amount of battery to run the low speed or the high speed, just that the low speed runs through a resistor to slow the fan down. you might as well be running the high speed fan since it will eat the same juice.

 

[scramblr]

I did mine, works great in the pits with the electric w/p on. Cools down literally in less than 10 minutes. Great mod!!

Here is a link that will help you get the switch started...
http://s197forum.com/forum/showthread.php?t=7016&highlight=fan

I did this about two years ago so I don't remember exactly how to do it if not I would just tell you. I do remember however that I tapped into the relay for the high speed fan in the fusebox.

I did mine like this wired to a toggle using the above thread

 

[KITT]

Thanks for the helps guys, very helpful!

 

[KITT]

I have an 08GT so I have the new resistor for low speed and this pic is of the plug to the fan. There are 3 prongs inside the plug. For testing purposes to find which one was high/low I put 12v straight from the battery to all 3 Prongs (1 at a time of course) and not one position will turn this fan on AT ALL! I guess I need the dumbass version with pics! lol I have the whole thing down except for where to send the 12v from my switch.

 

[tmcolegr]

Black (-) Ground
LG/VT (+) High Speed
LG/YE (+) Low Speed

 

[TexasKyle]

So you unplugged the fan, then just used 12v+ on each pin in the fan plug? IF so, that's why it didn't work. Gotta have the ground and the 12v+

 

[KITT]

Black (-) Ground
LG/VT (+) High Speed
LG/YE (+) Low Speed

So you unplugged the fan, then just used 12v+ on each pin in the fan plug? IF so, that's why it didn't work. Gotta have the ground and the 12v+

Thanks for the help I GOT IT! LOL I can read a wiring diagram so that really sealed the deal.

I was assuming the fan had ground already but of course when I pulled the plug off it lost it. Remove head from ass! thanks again.

 

[mot250]

Great info on how to re-wire the fans.

But if you don't want to re-wire the fans or you don't have time before your next track day, another way to go with the e-H2O pump wired to accessories-on circuit is to just run the heater on hot and full speed on the heater fan. The heater box will work as a radiator. This with the engine of but key turned to accessories-on.

I've done it this way at the drag strip, autocross and road course event and the car cools down also in about 10 minutes.

 

[05stroker]

Great info on how to re-wire the fans.

But if you don't want to re-wire the fans or you don't have time before your next track day, another way to go with the e-H2O pump wired to accessories-on circuit is to just run the heater on hot and full speed on the heater fan. The heater box will work as a radiator. This with the engine of but key turned to accessories-on.

I've done it this way at the drag strip, autocross and road course event and the car cools down also in about 10 minutes.

Makes sence since the heater core is nothing more than a heat exchanger or radiator itself.

I used to run the heater when the car would overheat on the street to help cool it down faster.

 

[TexasBlownV8]

You should change it to the high speed fan. Your using the same amount of battery to run the low speed or the high speed, just that the low speed runs through a resistor to slow the fan down. you might as well be running the high speed fan since it will eat the same juice.

Not true. Current draw with a resistor will be less than without one in a series circuit. Simple electric theory (Ohms law).