E-fan Question

[Guest SuperSon]

Found this schematic on wiring the relay. Besides the one that Martin has posted on the beginning of this thread this one might also help too

 

 

 

 

The two diagrams below show how to build and wire an auto relay switched 2-speed FORD TAURUS fan.

Parts needed......10 guage wire for the power circuit. 18 guage wire for the control cicuit.

Three relays..... 1) High speed relay, Tyco VF7-12V,70amps

2)Low speed relay and Aux relay, standard BOSCH relays

Two switches,,,,.1)Low speed temp. switch- Adj. Flexilite, FLX-31147 from SUMMIT.

2)High speed temp. switch from Standard Motor Products, TS-158 or TS-392.

I put the adj. low speed switch and the three relays in seperate relay boxes and mounted them in the engine comp. The high speed temp switch I mounted where one of the heater hoses went. Est. cost of parts, less the fan, is $50.00 . 10 guage wire is used in the power circuit and 18 guage in the control circuit. The 12V switched control circuit can be connected to any live connection with ignition on.

The control circuit shown is as follows..... When the temp. reaches your set low speed figure, let's say 190 deg.the low speed relay is energized thru pin 86, 85 connects to 87A of the AUX relay and pulls 30 of that relay, 87 of the low speed relay and 30 are closed sending power to the fan to run at low speed.

When the temp. reaches your high speed switch figure, let's say 210 deg. pin 86 of the AUX. relay energizes thru 85 and 30 releases from 87A of the low speed relay and connects with 85 of the high speed relay which thru 87 of that relay powers the fan to run at high speed.

ARE we confused yet?????

When the temp falls below the high speed swich figure the AUX relay will switch back to the low speed relay.

Therfore low and high speeds will never be on at the same time and you will have the following conditions...

1) No fan on.

2) Low speed on.

3) High speed on.

 

 

Edited March 29, 2007 by SuperSon

[mws]

This looks sound and is somewhat similar to what I did, but my use of the Flex-a-lite Variable Speed Controller on the low speed side caused additional complications as it is a ground switch. I also added more complexity by adding a switch (and indicator light) to allow me to manually disconnect the A/C compressor sense line. When traveling over 30 mph, there is no need to have the fan on when the A/C is on. So when I hit the freeway, I flip that switch to shut it down and turn on a bright LED as a reminder. I figure that gives me another .25 mpg on the freeway.... and since the parts to do were about $3.00, it was worth it. Plus, being an engineer, I actually enjoy the challenge of figuring out the logic of things like that...

 

If you want to use both speeds, this is a much simpler solution!

Edited March 29, 2007 by mws

[jj big shoe]

Here's how I did mine. I used an Imperial fan controller kit, but I replaced the t'stat with an adjustable one later. I'm pretty sure you could use a standard SPST relay and you own wires if you go with an adjustable and save some money.

Edited March 29, 2007 by jj big shoe

[Guest SuperSon]

Is yours a single speed JJ?

[mws]

In this schematic, he is using the fan as a single speed.

[jj big shoe]

Yeah, low speed only. I wanted to see if the low speed was enough to keep it cool and it definately is. Two summers in Florida and I haven't had any issues (other than when my water pump let go, but that's different). I figure why bother with the noise and current draw of the high speed if its not needed.