Electric fan a/c fan trigger.

Yes, just a Flex-a-Lite 678 with control. I will wire control tomorrow, now that I got help from "loginfailed". My fan clutch was failing, and I found the fan for $200 as new on Amazon Whse. So, I decided to do it. AC is on 9 months of the year here, and getting worse. Mechanical install was not bad, but they could improve the order of instructions. Nothing like you are doing, and I don't do offroad, unless I get it to the seashore at Corpus Christi! This is what it does.



Boy, I sure don't know how to edit on this site.....

 

OK, bear with me. I took lots of photos, and removed everything to get into the fuse box in the engine compartment, but could not. I let discretion be the better part of NOT DOING SOMETHING STUPID AND COSTING A FORTUNE. So, I make compromises for the time being. But the only real compromise is the AC Switch control wire. Maybe when I do the front struts (when it is MUCH cooler), I can get into the harness wire. So, thanks again to "loginfailed", I got to the wire I needed. I will come back and do a link to the complete install, for those that want to follow. Here we go, if I can get the pix right.

This is the specific relay location, looking at it from the drivers fender. The red wire points to it.


A little closer;

Since I could not remove (or disassemble) the fuse housing, I needed to get to the relay or terminal connection - I removed the relay;


The terminal in the socket that is needed is the FAR RIGHT. Terminal #5 in schematics. I took the relay to see if I could solder and smooth a connection that would fit;

Bad news for now, cannot solder to the relay terminals! But, it did leave me a good tinned 90 degree wire to work with.


Using some needle nose, insert the wire inside the rolled end on the "top" of the right most insert. The pressure of the relay tab will keep the wire in place.

Rock the relay gently back into place;

I drilled a hole in the lower casing of the FB on the engine side, just about 1/2" down from the top edge - brought the AC wire for the fan through the hole, and added a tie wrap as a strain relief, and soldered the connection.

Set the wire into a "routing" where it won't bother anything, and we are done. Sometime, when I get under the truck, and find the real harness where I might make a better connection, there is wire to do so in the right place.

Happy to say, it was only 102 in the drive this afternoon, but everything worked out just fine. This green wire runs when internal AC switch is on, and the Thermostat control was adjusted to what seems like normal. I can fine tune it. Oh, and since I wired both hots to hot, the fan will run cool down mode just fine. It takes a while to make these, so I will come back and post the full build as an album and give a link. And thanks, one more time, to those who helped me out!

 

As promised, but slow.... here is the whole deal. Thanks and props for the help.

https://www.tacomaworld.com/threads/flex-a-lite-678-install-in-2007-prerunner.565708/

 

Hey @Oldie2007 I switched out the trigger on mine.

With the trigger hooked to the relay pin, the fan goes on and off with the compressor. But, ideally you want the fan to keep running in between compressor on cycles. This allows the condenser to keep cooling.

I used the “ACID” wire on the A/C amplifier. This wire sends out a (-) trigger any time the A/C button is lit.

The A/C amplifier looks like this:


It is located directly above the glove box. If you remove the glove box you can see it up there:


On my 2014, the wire is violet and is located in pin location 25. I believe on a 2007, it is also violet, but is located in pin location 15.

My fan controller is able to accept a positive OR negative A/C trigger. Some controllers only accept positive. So if you need a positive trigger, you’ll have to use an SPDT relay to invert the signal.

 

Hey, thanks for your update. But I have the version with the thermostat, so it always runs if I have AC on, then uses the thermostat to switch on if I don't. Also, this wiring allows it to run for cool down after shut off. But GREAT detail, someone is going to like this!

 

You got that right! Thanks @loginfailed great write up and this was just what I was looking for.

I ordered up a couple 8 pin metripack connectors and a relay for switching (- to +) so I can make a harness for my Autocoolguy NB-100. Looking like this project is all coming together! Love this site, reminds me of how industrious the FJ forum used to be.

 

Well, next speed bump. The FJ has the A/C amplifier integrated to the control knob in the dash. There are no leads with constant outputs to tap onto. I was thinking about soldering a lead to the + terminal of the A/C on LED, but was worried that the slightly larger load (relay trigger) would disrupt the led or circuit board. I have an Autocoolguy PWM fan controller. They also make a timer relay for the a/c. This essentially takes the pulsing signal to the fan clutch and holds the high current side of the relay on for a few moments to allow the clutch to cycle as needed without interrupting the fan. This might be a nice solution for those that can't find a constant signal.

 

How many volts is fed to the LED to illuminate it? 3 volts?

 

I haven't bench tested it, but that was my concern as well. May not be enough to trigger the relay.

 

If you can solder a wire to the + side of the A/C LED, you can use this to create an output from it that is 12v and it will not affect the LED.

$10 PAC TR-4 Remote Turn-on Module , Black

https://www.amazon.com/dp/B0002J22BE

PDF manual
https://pac-audio.com/index.php?controller=attachment&id_attachment=67

 

Yeah, that might have just done it.

 

You rock for finding that. I had one on my 1st gen, and had it rigged to the clutch, and it did make the A/C wonky... once the compressor cut off and the fan did too, the pressure would rise quick and make them cycle on again. I've got one on the way for my 2nd gen, and wanted to do it "right" this time.

FYI for anyone using that controller that comes with the kit, ditch that POS. I never installed the one on my old truck, and upgraded to the old style adjustable one- it had the electric probe, but still had all the connections (including the power in & motor out) as spades. Well, I found out the hard way those spade connections ain't up to 30ish amps and are known to fail... hence why the new adjustable controller only has spade terminals for the trigger connections, the power in and motor leads are hard-wired. There's a reason NOTHING else in the automotive world uses 1/4" spade terminals for cooling fans. It's relatively cheap insurance to not get stranded or blow your motor up when your cooling fan controller fails... and it accepts + or - trigger inputs.

 

Have you guys observed better vent temps after the dual or single e fan install?

 

Just got my fan installed & wired using the ACID wire (for the indicator light, which doesn't cycle like the clutch) for the A/C trigger.

My driveway isn't baking in the sun in traffic (but it is 80+ & humid as hell) and I didn't jab a thermometer in the vents, but sitting at idle I can't see it blowing too much cooler, seemed like it was working close to 100%. Definitely an improvement from my old one that would rise to probably 70 degrees when the clutch would cycle off & kill the fans. Don't see any hotter than hell days in the forecast to really test it out.

 

@fb40dash5 how did you wire up the relay? I have been having trouble getting it to trigger the fan to come on.

 

Using the adjustable one (not the crap one with the mechanical thermocouple) you don't need a relay, which is what I've got... it allows both positive or ground triggers. I seriously, strongly recommend that one, with the hardwired power and motor leads. I've had lots of issues in the past with the ones that have spade connections for the main power & motor, the connections increase the resistance, you end up blowing the fuse, and if you don't catch it it could cost you an engine. I'm pretty sure I got mine plenty hot trying to dial in the controller temp setting, and the temp gauge on the truck hardly moved...

If you really want to use one of the old controllers that only accepts positive triggers, then what I'd recommend for the relay would be splitting off the ignition hot wire, and wire it to one of the switch legs of the relay, then run a jumper from that to one of the coil terminals as well. The other switch leg of the relay (use the normally open if you're using a 5-pin DPST relay) goes to the A/C trigger on the controller, and the other coil terminal of the relay goes to the same ACID wire on the truck. That takes your ground-switched signal from the truck and uses it to close the relay, and provides a positive signal to the controller.