This is a quick tip that I figured I'd share with everyone. You can use this a number of ways. Its entirely up to you. All you need to know is what wire to find! You're going to look for pin #17 on the CCRM under the hood. The CCRM is the "box" with a large harness attached to it. Its located on the bracket that the radiator overflow connects to. In that wire bundle, you're looking for the green wire with a purple stripe. In order to turn on the Highspeed fan, that wire needs to be grounded. You can simply pull back some of the insulation for it, attach your new wire and run it to whatever you want as far as a switch goes. On the other side of your desired switch, it should go to a good ground! Thats it...now whenever the car is on, and you ground that wire, it will turn on the high speed fan.
You can use a thermally activated switch, toggle switch, etc. The key has to be ON for this to work. There is NO chance of damage to the ECU or PCM provided you do this properly! Keep in MIND though that with the KEY ON, and ENGINE OFF, you are not charging the battery. I've accidently drained my battery in the staging lanes while cooling the car between runs so BE CAREFUL. My car is setup with a simple gator clip on the end. I just clip on to a bolt under the hood to turn the fan on when I need it.
(pics courtesy of allfordmustangs.com)
Note: As long as you didn't actually CUT the wire, with your switch in the off position, the fan will operate like normal!
You can use a thermally activated switch, toggle switch, etc. The key has to be ON for this to work. There is NO chance of damage to the ECU or PCM provided you do this properly! Keep in MIND though that with the KEY ON, and ENGINE OFF, you are not charging the battery. I've accidently drained my battery in the staging lanes while cooling the car between runs so BE CAREFUL. My car is setup with a simple gator clip on the end. I just clip on to a bolt under the hood to turn the fan on when I need it.
![tech17.jpg](/proxy.php?image=http%3A%2F%2Fwww.allfordmustangs.com%2Ftecharticles%2Fimages%2Ftech17.jpg&hash=f2962970cd8e024d00ca274201d60be3)
![fan50.gif](/proxy.php?image=http%3A%2F%2Fwww.allfordmustangs.com%2Ftecharticles%2Fimages%2Ffan50.gif&hash=2ac57cd4f8c335a295b6bf981733ec32)
(pics courtesy of allfordmustangs.com)
Note: As long as you didn't actually CUT the wire, with your switch in the off position, the fan will operate like normal!