I am installing e-fans in my 05 5.4L SCrew and need a switched 12v source for the thermostat. Thanks for any help.

 

I posed this question a few weeks back and didnt get an answer. I am going to run a wire in the cab and put in the fuse box. I already have ran wires for the LED indicators and manual switch. Which controller do you have? I have a MAD controller and i am trying to find a place and a way to mount it. I am zeroing in on it though!

 

Suggestions on running the power to your fans. Do not run them from the fuse box. The fans should be on a fairly short piece of 10 gauge wire. Use a relay and a short run from the battery to the relay. Then control the relay with power from under the steering column. The thick blue/green wire. Separate the insulation a little and run a wire from that out the grommet near the brakes and to the relay. This wire only needs to be 18-16 gauge as it will only care a fraction of an amp. This wire will go to a simple relay.
If you are using a 4 pole relay,

Ground pin 85
Connect pin 30 straight to the battery with a ten gauge wire
Connect pin 87 to the fans
Connect pin 86 to a wire from the blue/green ignition wire.

This way you are not 'messing' with the factory electric. Also, this way will supply much better power to the fans.
Any load heavier than a power mirror should be handled with a relay, or a direct heavy gauge wire.
Don't forget to fuse or circuit break the wire coming off the battery.


Chris

 

Chris,
Just out of curiosity, what advantage is there to tap into one of the main wires under the column versus tapping into the fuse box? Especially for just a fraction of an amp?

My MAD controller has all of the necesssary wiring and relays. I would never try to make the relays and controllers myself. but thats just me.

 

For the fraction of an amp there is no strong advantage of taping the primary key on wire over three or four of the unused fuse slots. Depends on how much you are pulling.

About half the guys posting on the e-fans are NOT using relay kits that have been sold with them.

A relay is not much harder that using an inline fuse, but I notice at least four posters in e-fan threads are using direct wiring for their fans. This can put a 30 amp load on the fuse box.
Only two of the usually free wires on the fuse box can handle that kind of load, and they are always on, not keyed.

There is one sneaky advantage to taping the wire at the ignition harness. If you go in for service and they pull your fuse cover, see an 'add a fuse' or some other hook up at the fuse box, they will tend to lay all problems on that, no matter how absurd. Under the column is hidden unless they start pulling panels.

Also, if you climb under the dash, the hot wire is very easy to find with the panel off.
At the fuse box, unless you pull the kickpanel off, it is very hard to see under there, and there are a LOT of wires.
Some folks get a little confused when you just point at a fuse box and say tap a wire.

I know you personally have no qualms about pulling things apart, or sorting through lots of parts. I've read your threads.

But some folks need/want things a little easier/less confusing.

What fuse position did you tap?
Chris

 

I havent tapped anything yet. I am trying to get the nerve up to do the swap! I think i am just going to use an add a fuse or just put a bare wire in one of the non-essential fuse spots.

jgross, which controller are using?

 

There is an ing. on wire under the hood and right next to the ac on wire, makes things convienent.

 

Why a switched 12v source? If the fan is running when you shut off, it probably won't run long enough to drain the battery.

Never did on any of my water-cooled VW's with their tiny batteries. Yes, I know, Fords are not VW's, but the theory is the same - in fact we've got a lot more battery for fans of similar power - should be less of a problem.

 

The fan i have pulls 25-30 amps at full draw. I dont think i want it running without the alternator running. PLUS i dont like to hear it running when i get out, it makes me wonder IF it will shut off while im inside or not.

 

Electric fans do normally run on after the motor is shut off. Helps you start cooler and helps defeat heat soak. On my last two cars with electric fans only, (Northstar and LT1 350) they ran about two or three minutes after shut down. On my Motor home, which has a large clutch fan, an electric fan and a separate tranny fan, the e-fans run a fixed ten minutes after shut down, or until temps drop. Never had a battery problem with any of them.
Chris

 

I may try it because i have my manual switch tied to the cigar lighter. In this configuration, it will run without the key (i think), which is good.