Electri Fan w/ Variable Speed Controller Installed...

Jul 27, 2004
AL Coast
For Reference, the vehicle mentioned is my 99 4runner. This will apply to nearly any Toyota Truck or SUV though...

First of all, what I bought:

FK-35 Variable Speed Fan Controller Kit, $109: LINK

This controller is something I ran across on another forum. Being an engineer, I know that by changing the speed of the fan depending on the difference in temperature of the coolant versus the desired temperature is MUCH better than a simple cycling of "ON" and "OFF" to maintain temperature. This varaible speed controller is a very similar technology that I use in everyday work to control pump speeds based on desired delivery. Also, this allows for a "soft start" with low amperage draw at startup. The controller can also be hooked up w/ an AC lead that keeps the speed at a minimum of 50%, and can also be hooked up to continue to cool after the ignition is off if desired. It comes preset for a control temperature of 180*, and other selectable temperatures are 158*, 166*, 194*, and 202*. The kit that I purchased comes w/ the controller, the heat sensor, all wiring, and instructions w/ illustrations. The controller can be mounted anywhere up by the firewall w/ the supplied wiring. It's about the size of a deck of cards. It's also a sealed unit, but since I already had the wire, I mounted it up by the Brake Master Cylinder on the firewall.

2000 Volvo S80 Electric Fan (eBay):

Very similar in looks to the Taurus Fan, I got this one simply because the shroud seemed to be a little bit larger and fit our radiators better. This turned out to be a moot point due to the way that I mounted it. The Taurus Fan (either 1-speed or 2-speed or any other similar fan) could easily be substituted here. The volvo fan is 17" tall and 24" wide and 3" deep and is stock on models V70, S60, S80, & S70. The 1994/95 Taurus/Sable Fans seem to be the most similar to the one that I used. The 1991-1993 Taurus/Sable Fans appear to be the same thing with just a different shroud. Since the OEM Toyota shroud is reused, the donor shourd shape doesn't matter.

Assorted Hardware:

(4) 1/4" x 3/4" long Zinc Bolts
(4) 1/4" Zinc Nuts
(8) 1/4" Zinc Flat Washers
(12) 5/16" Zinc Flat Washers


I removed my stock fan and shroud. The fan is held on by 4 nuts on the pulley studs. Take the top two off, tap the ignition to spin it over, then remove the other two. Remove the 4 bolts holding the stock shroud on the radiator. Remove the upper radaitor hose and pull the shroud out. You'll spill a little coolant here, but not too bad as long as the engine is cool. Now put (3) 5/16" Zinc Flat Washers on each stud, then followed by the OEM nut and torque the nuts back down when you get all 4 on w/ their washers that are used for spacer. THIS IS VERY IMPORTANT since this is what continues to hold the pulley on!

Take the Volvo Fan and use a hax saw, cutoff wheel, dremel, etc, to remove all the "tabs" that are sticking out around the edges and above the main body of the shroud. This cleans up the electric fan shroud so that it will fit nicely in the OEM Toyota shroud. Remove the control box on the fan (if it comes w/ one) so that you'll have a direct connection to the fan itself - VERY IMPORTANT.

Take your OEM Toyota stock shroud, flip it over so that the edges that normally seal against the radiator are facing up, then lay the electric fan w/ shroud in the OEM shroud - also with the sealing edges facing up, so that it's essentially "nested" inside the stock OEM Toyota shroud. Figure out where you want the electric fan to be mounted (I put mine as high as possible for water crossings, leaving a 2" gap at the bottom of the stock OEM Toyota shroud) and also make sure that the electric fan shroud isn't any "deeper" than the stock shroud. If the electric fan shroud looks like it would be too "deep" and prevent the reinstallation of the stock OEM Toyota shroud, then use the dremel or cutoff wheel to trim the "sealing edge" back away from the radiator so that the stock OEM Toyota shroud will touch the radiator and make the air seal and not the electric fan shroud.

To retain the electric fan shroud to the OEM shroud, I drilled (4) 5/16" holes through both of them while holding them in place. I then used (4) 1/4" x 3/4" long bolts w/ a flat washer on the head and the nut and tightened them down. Two of the holes were in the "top" of the shrouds and can been seen standing at the truck w/ the hood open (see the pics - the zinc/silver hex-head bolts on top of the shroud are the ones that I installed). The other two went in the bottom of the shroud, one on each side just to hold the bottom into place snugly against the stock OEM Toyota shroud. You may need/want to cut out some slots in the bottom of the donor shroud so that the air can still flow from your stock shroud through the slots and to the electric fan. If you want, you can also remove the lower lip of the donor shroud completely. The more you remove, the better air flow you will get from the lower section of the radiator and the more efficient the fan will be at cooling. I didn't do either of these and I'm still getting sufficient cooling.

I mounted the Controller on the Firewall Pinch-Weld up by the Brake Master Cylinder. The wires were easy to run w/ only 7 total to run. One set of (+) & (-) from the battery to the controller, one set of (+) & (-) from the controller to the fan leads, one from the temp sensor to the controller, one IGN lead to keep it from running w/ the vehicle off, and one for the AC relay to trigger the 50% minimum speed when the AC is on. Oh, and the temp sensor is a sealed type that is prewired and just inserts between the radiator fins - very simple to install.

Overall, I'm very pleased w/ the install. The fan is nice and quiet and doesn't run when not needed on the highway and the speed is varied according to the need. It's a big difference in the sound of the engine w/ the parasitic fan removed due to the reduced noise. The response seems to be improved as expected.

Total install took about 2 hours, but that was with the problems that I had w/ the Volvo Fan Controller that came on it and to also figure all this out. With a good understanding of what to do and with a little planning, this could easily be done in an hour.

Last edited:

John Smith

In the garage
Jun 7, 2004
That is a damn good write up.

I *highly* recommend you install a warning light if possible to let you know when the fan is not running. I have known three people personally who have toasted their engines when their electric fans failed. Electric fans are definitely cool (no pun intended), especially if you do a lot of water crossings but I will never run one.

I truly hope you have good luck with yours.
Top Bottom