Electric Fan

[tacowillys]

I know alot of people have converted their vehicles to electric fan so I wanted to share a link for a good write up.  I used the same fan on my CJ7 for several years without any problems.  It fits the radiator almost perfectly. I just use the low speed setting.  I am not running relays, and found out that the high speed setting will burn up a 30amp switch.  So if you plan on using it that way definitly use a similar relay setup as suggested.  http://www.creeperjeepers.org/Electric%20fan%20install%20in%20a%202.5L%20TJ.html

[PJ1]

This is a good write up for the correct wiring and install of an electric fan. The ARB type of switches are available thru NAPA part# RS1098 and Fleetpride also sells Cole Hersee if you want the fancy ARB style that has a fan printed on the switch. The one thing that I noticed that was unclear was the reason for the diode. The diode suppresses the high transient voltages produced when the magnetic field of a coil collapses. The voltage produced when this "field" collapses is about the cube of the input, (its a little more indepth than a cube of the input but you get the idea) and the current is in the reverse direction. If this voltage was able to reach the PCM it would kill it so diodes are installed to clamp or freewheel this voltage within the switched devices and protect the PCM. Hopefully this is easy to understand and better explains why this diode is a must in computer controlled vehicles.