I have been running my homemade efan for a while now, over a year, and I want to wire in a toggle switch to turn the fan on at the track without the truck running. L-menace directed me quite well in the installation of the kit, hopefully he can chime in if no one knows the answer. Thanks in advance,
Justin

 

kinda busy at work right now.

If your fan has 2 speeds, Hi and Low, you could run the high side off the temp sensor and the a/c and the low side off a toggle switch.

you could with the help of some relays add a toggle switch to the same power you are running now, but that would take considerable wiring and a "Few" relays. That would be a PITA.


Just a thought, You could put 2 toggle switches on for your A/C trigger wire, one to break the circuit so you aren't sending positive through your fuse box and frying things, and another that is tapped into a 12v constant to send the power to the fan wiring harness.

Or you could unplug the A/C wire in the fuse box (under the hood) and wire it in to a constant hot wire, and that will turn the fan on constantly, until you pull it out and put it back to the A/C.

 

Ok, so basically, could I put a toggle switch in line with the hot wire to the fan to "disengage" it from the relay. Then toggle in another wire after that switch, to provide 12 volts "on demand"? That way, I would turn off switch #1, and turn on switch #2. Then when I want to run my fan normally, I would turn off #2 , and turn on #1? Doing it this way would save the relay and not have a feedback through when I toggled on my 12 volt track switch.

 

[QUOTE=l-menace]..Just a thought, You could put 2 toggle switches on for your A/C trigger wire, one to break the circuit so you aren't sending positive through your fuse box and frying things, and another that is tapped into a 12v constant to send the power to the fan wiring harness...{QUOTE]

You can isolate the signals with a simple diode.

I did my own custom wiring on mine. I'll try to post up a sketch sometime soon. But for right now I'll describe what I did.

I used two relays, one for high speed and one for low speed. I fed the high speed relays main power from the battery through a 40 Amp thermal breaker. I then fed the main power for the low speed relay through the Normally Closed contact on the High speed relay. (This should be the 87a Terminal in the middle of the relay)

By doing this this way there is no way you can accidently put power to both the high speed and low speed circuits of the fan. That would cause the fan to burn up and possibly cause a fire. I actually see where some vendors don't put this circuit protection in their fan wiring.

I decided I wanted my low speed to come on with the temp sensor and the ac and only turn my high speed on with a manual switch for cooling at the track.

For the control power on the low speed relay I wired one side of the coil to ignition +12V, and wired the two triggers for the temperature sensor and the AC to the negative side of the coil. I used two standard 1amp diodes on each of these trigger wires to isolate them from each other (very important).

For the high speed relay you can ground one side of the coil and have a switch inside the truck that switches a constant +12V to the other side of the coil when you want the high speed to come on. Or vice-versa and send a ground signal from the switch.

But the trick in this whole set up is to have the one relay feeding the other with the normally closed contact. When ever the first (pass through) relay is triggered it over rides any logic needed to trigger the second (low speed relay). This method is also good in case you had trigger problems (bad sensor), or a malfunction with the low speed relay (the one that gets used all the time), you have a manual back up by using the high speed relay with the manual switch.

 

http://www.svtgalleries.net/gallery/...=17794&cat=500

Here's a sketch I threw together.

 

Damn Impressive@! good work

 

Thanks Bro.

I've been running this setup on mine for almost 2 years on a JDM fan. Nothing against JDM because this is a top quality kit, but I decided to do my own custom wiring for 3 reasons:

1st to prevent accidental switching of both high and low side of the fan. If you ever try this the fan actually slows down and starts over heating.

2nd not to have an entirely seperate relay just to isolate the AC and temperature signals, diodes work just fine. (I did use a beefier 3 amp diode on mine, but any standard 1 amp will do for just a relay trigger)

3rd there was no relay on the high side and their kit had you run a high capacity switch under the hood. I wanted the high side switch inside the cab but didn't want to run high current wires unnecessary long lengths to get them to a switch inside the cab (this is bad practice anyway). The only snag in using a JDM fan is that I needed a relay for the high side just a little heavier duty than the standard 30amp. After rummaging through my drawers in the garage I found a 40amp in a standard size. Orginally came off of a DEI remote start. A 30amp would work but would eventually wear out. A 40 amp has given me no problems, and has a 90 amp inrush capability , which matches up with the high side of the fan pretty well. A standard 30 amp on the low side is all that is required and should never give you a problem.

 

Very nice work and thanks for the replies guys. I will have to add this one to the list of stuff to do this month.