Wiring a Fan

     I am upgrading the sound system in my '94 jeep grang cherokee.  Im going to take out the stock amp under the rear seat and replace it with a Kenwood 4 channel amp.  On the other side under the rear seat Im going to mount an Autotek amp for my sub.  Thats going to be about 600 watts RMS under someones butt.  I really dont want to fry either amp so i want to add a pair of dual 60 CFM 12VDC computer case cooling fans.  The fan wiring has 2 wires coming from it, a black and a red.  Obviously these are negative and positive, respectively.  I was wondering if there was a convienient/cheap way to make an automatic switching device so I dont have to worry about flipping a swith every time I crank my music up.  I want a psuedo-remote wire set-up.  I don't know whether it's feasible or not, but thats why Im asking.   Thanks for any help.--Mark

What you need to do is add a relay. You connect the relay to the remote wire on your head unit . The fans will then turn on and off with the radio. If you need any more help don’t hesitate to ask.  

Here is a diagram of how to wire it

 87 - Constant

 86 : GROUND  30 - Remote Wire Accessories ( amps, EQ's fans  )  85 : Remote Input from HU  87a: NOT USED

Thanks alot for the advice.  you guys are a great help!--Mark