This is the electric fan setup I've been using on my beater project for a while. I've recently been able to test it in 90-plus degree weather, and it seems to act upon pretty reliably, so I finger comfortable writing about it now. The staple musical theme is to use the stock XJ buff "layout" on the radiator, merely using an blower in lieu of the mechanical sports fan. This substance putting a one-on-one electric fan inside the mechanistic devotee's shroud, with an independent temperature tack turning the fan along and off as needed. The stock condenser fan is too notwithstandin present, merely it is allay under the command of the ECM and isn't involved in the convention cooling. It's possible to go beyond this frame-up with a blue-collar override switching or a lover comptroller or whatever, merely I haven't done any of that for now.

The premiere step is to eliminate the machine fan meeting place and gain room for an electric fan motor. Some hoi polloi chop the nub off the ancillary bracket with a sawzall, but I replaced my add-on bracket with one from a YJ, which got free of the fan nub and besides moved the alternator five inches higher (control here).

Next is the fan itself. I washed-out a lot of time looking at options and eventually settled on the leftist-side fan from a 3rd or 4th generation Ford Taurus. About of the Taurus lover swaps are for the single big fan from a 3.8L engine, but the 3rd and 4th gen engines employment two fans next to for each one new, and this mod uses the left-handed-hand fan from those setups since IT is a trifle larger. Specifically the left-handed-side winnow is approximately 14.5" outer diam, while the opening in the stock mechanical fan hide is roughly 15.5" inside diameter. This lets the buff drop into the stock shroud with only approximately underage modifications. Here is a pic showing the fan session in the shroud before any modifications

In order to make the fan fit into the shroud, I chopped off the excessiveness plastic parts and trimmed the outside adjoin sol that information technology would fit cleanly. And so I used 1/4" chromium steel carriage bolts, spacers, and nylon lock nuts to secure the fan into the center of the shroud.

Examine for fitment and pee sure nothing interferes. You can buoy realise from the pic below why the mechanical fan nub has to be removed first

Now for the electronics. These fans have 2 positive wires and one earth, merely there is only one indirect on the motor. The way these are wired upward in the 3rd gen Taurus is that single of the force wires goes through an inline resistance that kicks the voltage down, which provides a "low speed" cognitive process, while the another wire goes straight through and provides a "high speed" operation (which is rattling the "normal" speed). You can cause this too if you neediness, even so for the purpose of this write-up I am just doing a unvarying unmolested input that bequeath turn the devotee along and off accordant to temperature.

I dependable a bunch of switches (over $100 in rejects) and the most consonant and reliable thing I've found hitherto is a two-pin switch from posthumous-80s/early-90s BMW models (Four Seasons split number is 36511, the one I bought from Chinese cabbage was ATM part number 1435033). Accordant to the glasses, it is supposed to come on at 95c (203f) and go off again at 90c (194f) which means it should only come on after thermoregulator is fully open and go off again when the thermostat is starting to close.

Unfortunately the switch uses an M14x1.5 thread, so it will not fit into some of the well-worn openings. You might be able to Mandrillus leucophaeus and tap a hole in the front of the thermostat housing for this, but I already have a gauge sender thither so I had to use something else. I also tried drilling and threading a 3/8 NPT to 1/4 NPT adapter fee but the sidewall of the fee ended in the lead being to a fault thin and would crack after a few heat cycles. The thing that finally worked for me was a 4" long 1.25" OD brass instrument pipage nipple installed in the upper radiator hose down. I drilled a 1/2" hole and and so used a M14x1.5 fine-pitching stainless steel bolt to make a thread in the pipe (a tap would work better just I couldn't justify the $40 for a single use dab). Brass was soft enough for this, and was diluent than the galvanized operating room plastic pipe. If you go this route make sure the pipe is long enough to chop the threads off the end, since pressurized coolant bequeath go on dormie the threads and prove to leak. Present's a picture show of the substitution installed.

From there it's just a simple relay to reverse the fan on and off. Since everything is by the battery this is pretty unsophisticated to apparatus. In my case I chose to run constant battery power to the switch and fan, so run the ground leg for the shift to the relay, since this is similar to how the stock fan operates, and should be easy to telegraph up an overthrow switch (short to ground basically). Present's a pic from the rear, using an earlier test switch. You backside date the relay on the fender wall.

One artifact of using constant barrage power is that the fan leave run after the engine cuts off if the switch is closed. This happens about everytime I repulse the jeep, but the temperature of the coolant at the substitution is knocked down pretty nimble so the fan does not run precise long-staple. Really IT will cycle a some times as the hose heats upwards from the coolant that's still in the locomotive, then IT cools inactive, heats up again, etc. I've never had whatever problems with battery draining OR anything, but if you want to feeling many rich you can tie the switch into firing power from the PDC if you prefer.

Some other option worth looking into is a leash-pin switch for the same generation of BMW vehicles, which provides two item-by-item switches at 194f and 207f respectively. In conjunction with the 3rd gen Carlos the Jackal inline resistor, this could be used to drive the "downcast-speed" and "full-speed" pins on the winnow motor as well.

Anyway in the former fewer months of testing I've been very pleased with the fan, and the setup has performed pretty so much the comparable as the old mechanised setup did. Driving down pat the main road the bore is below the 210 hash mark, but when I halt at a red floodlighted or a private road-through window the approximate starts to creep into the 210 hashmark, so the fan kicks on. Once I part moving again (Oregon if the outside temporary worker is cool enough for the fan to do the work alone) the temporary worker will drop to below 200 and the fan will go over. There has only been once where the secondary devotee kicked on imputable ECM program line, and every bit expected the temperature dropped very quickly with both fans spinning.

Boilers suit very glad I made this modification as it gives Pine Tree State more control, and eliminating the mech fan also eliminated a noticeable amount of sweep up on the serp belt.

Here is the terminal parts number for my installation

stock mechanical fan cerement
left-side 3rd OR 4th propagation Taurus sports fan (3.0L)
four 1/4" carriage bolts, lock nuts, and misc spacers
two-pin BMW sports fan switch (Four Seasons 36511, or NAPA ATM-1435033)
cardinal relay

99 Jeep Cherokee Xj Dual Electric Fan Vs. Factory Fans

Source: https://www.naxja.org/forum/showthread.php?t=1035194