XJeepWerks

My Xj was just wrecked last week, which took out the whole front end, including the radiator, electric fan, and clutch fan. I've been planning on an e fan swap for a while now... and what better time?

The way I'd like to wire the fan is so that low speed comes on when the engine is running, but turns off automatically when it is not and so the high speed can be turned on manually by a switch inside the cab or by the stock e fan wiring. (The switch is for a backup incase something in the system fails, and incase I know I'm going to be pushing my rig pretty hard and want to give it that extra cooling boost.)

My questions are, would the stock e fan wiring be able to handle the startup amps the taurus fan pulls as well as the stock e fan? And, I'm pretty good with wiring, but I always get lost when it comes to relays... would somebody be willing to make up a rough wiring diagram for me?

FOXxX

Your stock e-fan wiring will not be able to handle the draw the taurus fan will pull so a new wiring system will need to happen - not hard just time consuming. If you go to your local car audio store theyhave relays , typically bosch, that can handle a 30A draw and that is plenty for the e fan. You'll need two relays for this app.

On each relay you'll attach:

- +12V 8 guage wire to pin 30
- High/Low wire to pin 87
- Gnd to pin 86
- Ignition to pin 85

For the +12V and High/Low wires you'll need to solder them to the relay and at each splice. That e-fan will put too much strain on spade connectors and the wiring will fail.

The way I have mine setup is that the low setting comes on with the ignition and the high comes on with a switch in the cab. In order to make this work you'll have to wire the +12V for the low relay from pin 87a on the high relay. Dont wire from 87a and the battery or you wil have major issues. So to clear this up:

High relay only:
+12V to pin 30 (soldered)
high wire on pin 87 (soldered)
gnd to pin 86
Ignition (manual switch) to 85

Low relay:
87a (from high relay) to pin 30 (soldered)
Low wire on pin 87 (soldered)
gnd to pin 86
ignition to 85

its early and still having coffee. hope this makes sense to you.

XJeepWerks

Ok thanks, that helps a little bit to clear things up. If I want to run a SPDT switch (high-off-low) what relays would I need and how would I wire them? I've got a Hella 40amp relay sitting around I can use, but I've heard the Taurus fans pull close to 70amps at startup.

FOXxX

I have my E-fan sitting on two 30A relays - 1 for high and 1 for low. As long as you solder the ones I spoke about earlier - you'll be fine. The fan might draw 50A's on spin-up but once the fan is spinning, it only draws about 6A total. Spin-up takes about a second and I promise you will not burn up that relay.
I would also not recommend putting the low setting on a manual switch because of the obvious - forgetting to turn it on. However if you must, keep the wiring the same as above except for the 85 pins. Those pins will come from the respective high/low (+) trigger on the switch.

XJeepWerks

What I wanted to do was have that SPDT switch (High-off-low) only have power when the ignition is on, so that way I would just leave the switch on low all the time and it would turn off and on with the engine. Doing it this way would give me the ability to turn the fan on high when necessary and turn it off when necessary.

XJeepWerks

How does this look?




Where would fuses be needed?

mjonesjr

Why not just run a temp sensor to turn the low side on and off at the desired engine temp?

Then run a switch for the high side.

XJeepWerks

It's easier and quicker to run it this way. My Xj is currently wrecked and waiting for the insurance check to repair it. It's my daily driver and needs to be back on the road asap.

FOXxX

The fuse is going to be on the +12V line to the relays. Make sure it is a 40A fuse - I used a Car Amp fuse holder and wires for the install. Came with all the necessary materials.

The low relay can have a trigger on 85 that comes directly from a ignition source rather than relying on a manual switch. It doesn't matter if the ignition source is constant, if you wire it up as I explained in the initial post, you will not have any issues. The only relay that needs a manual switch is the High relay.

Yes the diagram you displayed will work just fine.

XJeepWerks

Alright, thanks for clearing everything up for me. I will be picking up a fan this saturday at the junkyard.

dubbleJ's

Im looking for some info on this swap as well. With this diagram what gauge wire should I be using and where? Should I use 10ga to the relays from the battery and then 14 or 16ga to the switch?
With relays do I need a high amp 2way switch still or can it be a 20A On-off-On?
I havent been able to find a 50A 2 way switch yet and have also read its not wise to run 10ga wire into the cab without relays, elthough I did plan to use fuses on both lines from the battery.

Thanks for any info!!

wikiwaugh

Hey, I know this has been a while - how did the switch wiring work out for you? I'm starting my install today and I like the setup you've gone with here.

Thanks!

96blackxj

i did mine the easiest way... i got a big relay from napa it handles continuous 90 amp draw... i got 6 gauge wire from the battery to the relay and 8 guage from the relay to only the high side on the fan.. then i took the stock wiring off the ac fan and extended it to the relay so the ecu will turn on the fan whenever it needs it...

when i got my jeep my ac fan was already wired to a toggle switch so when i go off roading i turn it on always but driving around city it never overheats... it will go a litle over 210 then my fan will automatically turn on and cool off..

works well that way if someone borrows my jeep i dont have to make sure they turn a switch on or off dummy proof

wikiwaugh

That's a great idea, I wonder if a wiring harness is pre-fitted in non a/c models...

I just wrapped up all my wiring, with the same setup as above, just haven't put the fan in

96blackxj

i dont know but i assume if the axillary fan is there then the wiring is there ill do a writeup on how i did mine sometime today or tomorrow so everyone can see, my jeep never gets hot