Hello all, been a while, been working on a triple fan mod and was hoping to get some clarification as to where best to tap for the double fan controller to handle fans 2 and 3.

That's the triple fan setup and fan controller in question. Where is a good place to tap for Ignition, Battery+ and Ground?

I was thinking of tapping fuse 8 for the key on/off ignition signal since it's not actually hooked to anything and tapping both power and ground from somewhere in the passenger compartment or junction block but I was curious if anyone else had a better hookup or place to tap inside the cabin (not engine bay). Worst case I can run another couple wires to tap battery and ground directly but I'm hoping to avoid that.

For reference I'm using this wiring setup for the controller. The fans will be switched on/off by a relay and fuse box I wired up on the drivers side of the engine bay pulling from a separate voltage distribution box that taps to the battery. No shutoff or AC planned right now until I get around to fixing the AC (not a high priority since usually windows down is enough.)
also the sensor/sender wire is tan not violet but otherwise the same for this setup.

The controller pulls about 5-10 amps so it shouldn't be an amperage problem either but I want to be sure.

 

does your auxiliary fuse box draw power directly from the battery? if so, that's where you want your battery plus. attach your ign to pin 87 of your relay, and pin 30 to your in-cab fuse box (that one is triggered by key). ground goes to whatever nearest ground. for mine, I put a ring terminal on the ground, then ran a self-tapper to sheetmetal after removing all the paint. I will post a picture of my setup tomorrow

 

I've got a bit of a different setup from the one in the guide that's an extension of my current 2 fan wiring setup.

I'm using 5 pin relays where the voltage signal is triggering them (in this case if one fan cuts on another one triggers) But with the new relay box I'm having the 2 fan relays be triggered by the fan controller sending a signal to cut them on until the temperature drops back down. (leaving the last one stock triggered by the ECU as normal by temp.)

Or at least that's what I've set it up to do. I'll post some pictures of my relay/fuse box when I have some time in the next day or so but having tested the relay with a simple on/off signal it seemed to work the same as the 2 fan setup. One of the reasons I picked that fan controller is because it could take a stock temperature sensor's output and be programmed to utilize it instead of needing a second sending unit. Plus you can program the outputs to cut on at different temps. So I was hoping to have the fans cut on at different temps as needed, one at 190, one at 206/210, and the last one at 212/216 which is the default behavior of them while keeping the engine overall cooler without relying on mechanical clutch fans and really only having 2 going if it'd idling for a while (sitting in traffic, sitting at along drive through, etc) or 3 going when it's super hot out or the engine is working extra hard.

Each fan can pull 8,000 cfm and the radiator is a bit overspec'd able to passively cool things and maintain temp so long as the jeep is moving at about 25mph+

As is the fans only cut on when the ecu tells them to but I was hoping to make things a bit more consistent and efficient.

 

Do you have a high amp alternator? I cant imagine how many amps those things draw but think worse case scenario which sadly will be way more frequent than you think...lights on...hot...blower going...and stuck in bumper to bumper traffic at idle...oh yea and its raining...my stock alt cant keep up with only 1 elec cooling fan

 

Already accounted for. The headlamps were replaced with lower power draw ones as were the fans. That was a major concern tbh and I did a lot of calculations. The headlamps if I were using 120 watt bulbs would draw 8 amps total. I've only got the 60 watt ones they came with so closer to 4. Because watts divided by volts equals amps. Confirmed with my multimeter.

The fans draw 15 amps each plus another 15 for the engine itself per the fsm.

So that's 68 total. The stock alternator puts out 117 amps
(Again per the fsm, and tested with multimeter) and while I'll be upgrading it that leaves me with about 50 amps of overhead for stuff like the radio, cb, etc in ideal conditions which draw less than 6 amps each at full draw.

So far with two fans going, headlamps on high beam and radio at loud enough to buzz the speakers the lamps don't even dim when the fans spool up.
Also my ac is currently disabled but that's a different problem because I'm missing parts... And it doesn't get that hot here normally. Usually windows down is enough so I haven't worried about it.

Given all that could it just have been a weak or failing alternator in your case?

 

8000 cfm! Each! Holy cow. What fans are these? The most flow I've seen is around 2000-3000 from a single 16" or 17". Why three? One of those fans could cool 4 700 HP Ultra 4 cars. Anyway, it's always best to control fans manually. A nice 3 button panel from billet buttons and turn them on and off from the cockpit.

 

Spal 30100435 10" fans

Just double checked it's 847 but just two is enough to pull it down temp wise. Nothing wrong with a little overkill.

I did think about putting some manual controls in the dash. Probably still could by using the extra pin on the 5 pin relays just having them trigger an alternate system and disable the controller with a switch that triggers the disable pin. So the option to have my cake and eat it too is there 😂. Just throw a switch that triggers an override relay capable of handling 50 amps, pushes a signal to controller disable, and have a potentiometer between the battery and the fans somewhere in circuit. Definitely doable.

 

Here's my setup. As a reference, I use the Trinity Fan Controller from NickInTImeDesign.

Battery to fuse box. the empty fuse... well I just discovered that. the tweakers that stole my jeep replaced the fuse with a short wire, now I have to replace that fuse.

Fused positive to relay (also discovered today that the tweakers managed to rip one of my cables out of the terminal board. I will be replacing soon.

the controller

As shown, I have fused hot to pin 30, load (fans) to pin 87, switch to 86, controller to 85. the controller has a temperature probe and one side of the switch in cab. the other side of switch is that red conductor on the right side.

pretty much like this

 

@SirCyber This is very similar to what I'm trying to do. From what I can see here you've connected one end of the relay to the fan controller, and the other to voltage. Does it matter what direction that's setup in? does the controller have to be the ground lead or can it feed enough power to trigger the switch. It wouldn't be a big deal for me to connect the ground lead from the relays to the voltage bus and just wire it that way given how my relay/fuse box is wired.

This was my original diagram, only the bottom two instead of having a theromstat trigger would be activated by the fan controller which is pulling in data from the temperature sender. Also I ended up with a dedicated power distribution bus instead of tapping the oem block and hooking that up to the battery with some 4 gauge wire. The wires should be hooked up to the terminals as listed though with bat+ > fuse > Relay > fan >ground for the power and trigger signal > relay > ground for switching them on/off. right now this is how my 2 fans are running, with one fan tripping the second relay.

This original diagram was based on my existing 2 fan setup but of course with different temperature triggers I had to do some modifications to the design.



Here's the current layout.


Bottom two black wires are the ground leads for the fan and headlamp relays they're separated to prevent any sorta of bleed or crossover.

The two red wires with heat shrink go to the fan controller and are the 190 and 206-210 degree temp signals.

The three red wires are the voltage lines for the fans, there are three more black that go out to the fans.

the two bundles are the headlamp wires I haven't gotten around to doing yet because the current draw is enough but should allow for more amps if I need it after an alternator upgrade.

all the wire is 8 gauge except the 4 gauge going from the red voltage bus which goes to the battery and alternator terminal.

It looks like a mess but I usually keep it strapped down while I'm unfinished to keep it from being a problem. It's over on the passenger side in a wide empty space near the wheel well



This is the temp sender tap which goes to the fan controller.


Wires are zip tied in place and routed via the existing cable comb down to the fan controller, the thicker wire is the voltage line to the alternator/battery.



Down into the passenger compartment for the fan controller.



And finally the Voltage lead to the voltage distribution bus, currently not hooked up because I haven't got it all wired up yet but you can see part of the old system that operates electric fan #2 which will be getting removed once I'm done.

 

so I've never run a relay to a ground bus. in Nick's diagram, and in my application, the ground is on the ground side of the fans. The only deviation I made was the 12V Ignition, which goes to my in cab switch, and the other side of the switch comes back to the fuse block.
Easier to explain as such:
Pin 30= High Voltage from source
Pin 87= High Voltage to Load
Pin 86=Low Voltage from coil load
Pin 85= Low Voltage to controller

You can interchange 30 and 87, and you can interchange 86 and 85. All my fan grounds are daisy chained together to keep everything tidy underneath the top rad support. they share the same ground point as my controller. Pin 85 and 86 are not a switch, they are connected inside the relay. they rely on an external switch (controller in both of our cases)

4AWG is huge if all you are controlling is fans. Better safe than sorry, but pleasantly overkill. As a reference, 4AWG can handle 85 amps. I'm using 12AWG myself, good for 20amps. 87 is set up for a circuit that is normally open(the contact rest on 87A) and 87A is set up for a circuit that is normally closed and when the circuit/relay is energized it opens the contact. 87a and 30 are connected when the coil is not energized. When the coil is energized, 87 and 30 are connected.

As a side note. I have a stock alternator. Even at idle, it more than handles the full amp draw of my three fans with absolutely zero bogging or dimming of any lights

 

@SirCyber That's exactly why I'm using 4 gauge. I wanted it to handle upwards of around 60 to 70 amps at the voltage bus for both the headlamps and the fans at their maximum rated draw. Still have plenty of wire and terminals left over from when I was re-doing the battery cables which were corroded from 20 years of age so I used that.

I guess my question is, does it matter if the switch is on the ground side or the signal (voltage), side of the trigger? so does it matter if it's Power > controller > Relay > Ground vs power > Relay > controller > ground.

In my head the controller should be on pin 86 and ground on 85 since the controller is completing the circuit to ground when it sends the signal triggering the switch.

Right now it's load > relay > ground for the second fan, the "load" being triggered by the voltage going from the stock relay to fan 1 (ECU triggered) thus when one cuts on the other one does right after with both pulling 15 amps and no appreciable voltage drop on the voltmeter inside the cabin. It stays right up against 14 volts and the battery stays charged (even with 20 amps allocated for the engine I still have about 30 to 40 percent overhead from the alternator during normal use at maximum draw since I swapped the headlamps.)

the Relays are rated at 30 amps and it doesn't matter which signal because both low and high voltage are below the relay's maximum tolerances for trigger signal. Or at least that's what I've been led to believe,

 

that is incorrect. The rated amperage is for the high voltage side. you will fry your relay if you try to pump 30 amps to the coil. It's a fine wire coil. The primary purpose is to safely route voltage across the higher amp side while not shorting your switch. switches are normally only rated for 2-3amps. This is very important for safety.

 

Huh, well it's good I haven't burned that relay yet but that's why I'm double checking everything before I power the new setup on probably over the weekend if weather permits.

So to verify the controller should output a couple amps to the relay trigger?

 

yes... not many. enough to energize the coil

 

That's just unmounted, open-air CFM. Their efficiency will increase to ~1000 CFM easily when mounted to a decent shroud with separating vanes. I'm using 3 of them and my temp stays between 195-205 regardless of temp or AC usage; even just 2 can keep that up unless I'm going up a steep hill.

I think the 15A is just for the initial kick-on, they should use around 10A~11A when running.