Slant Six Forum
https://slantsix.org/forum/

Electric fan switch?
https://slantsix.org/forum/viewtopic.php?t=46823		 Page 1 of 1
Author:  Rick Covalt [ Fri Oct 28, 2011 4:19 pm ]
Post subject:  Electric fan switch?
I need a little guidance on what type of switch to buy for what i want to do.

I understand how to install an electric fan powered through a relay. I installed the one in Ryan's dart.

Here is what I want to do. 1) Manually by-pass the temperature controller and force the fan to run. 2) Have fan "on" running through the temp controller.(normal operations) 3) Have fan manually "off"

So am I just looking for a 3 position switch? With a center off position? This will be mounted in my instrument panel with my other gauges. If you have any recommendations I would greatly appreciate it.

Sorry for being so dense in the noggin about electrical stuff.

Oh, and it would be nice if it had a light when in the manual off position so I didn't forget it.

Rick
Author:  Rick Covalt [ Fri Oct 28, 2011 5:23 pm ]
Post subject:  Like this?
I think I got ithttp://www.delcity.net/store/Chrome!pla ... 789186.a_1
Author:  emsvitil [ Fri Oct 28, 2011 5:29 pm ]
Post subject: 
You might want a Dual pole / dual throw switch.

One side for controlling the fan, the other for light/led indicators.


Check out digikey for switches....


If you use 2 relays, you can have the center position as automatic, then have one of the ON throws break the connection with the second relay (so you can have that ON throw ligtht up a indicator)
Author:  olafla [ Fri Oct 28, 2011 8:23 pm ]
Post subject: 
Rick, if you haven't got any relays already, I recently saw a post where a large, old-fashioned heavy duty relay was recommended for the el. fan. Fans often draw quite a lot of current (6-8 amps), and the relays are frequently switching. The person in question actually used a starter relay for a Peugot or other small import car to power the fans.

My 2¢.

Olaf.

BTW, nice switch, it actually looks like quality products used to look!
If it is the same toggle switch as this, you have a very good price too!
Author:  emsvitil [ Sat Oct 29, 2011 1:17 am ]
Post subject: 
Simple circuit with inidicator LEDs

parts:

1 DPDT center off toggle (dual pole , dual throw)
3 resistors (500-1000 ohms, lower rating=brighter led) R1,R2,R3
3 LEDs (yellow, red, green) Ly,Lr,Lg
3 diodes D1,D2,D3
1 auto lighting relay (T86,T85)
1 temperature switch (grounds when on) TS


Toggle has 2 sides, 3 terminals per side T1,T2,T3 (side 1) T4,T5,T6 (side 2) T2&T5 are center terminals. T1,T2 and T4,T5 connect or T2,T3 and T5,T6 connect or nothing is connected in center position

Get a piece of paper to draw the circuit, I'll show the parts.

IG=Ignition +
GRD = ground

Toggle:

T1 T4
T2 T5
T3 T6

Connect T1 and T6 to ground
T1-GRD
T6-GRD

T3 isn't connected

Connect T4 to temperature switch
T4-TS

Connect IG to one side of the relay coil
IG-T86

Connect the other side of the relay coil to T5
T85-T5

Connect IG to R1, R1 to Ly, Ly to T2
IG-R1-Ly-T2

Connect IG to R2, R2 to Lg, Lg to T5
IG-R2-Lg-T5

Connect IG to R3, R3 to Lr, Lr to D3, D3 to GRD
IG-R3-Lr-D3-GRD (diode current flow IG to GRD ->|- )

Connect R3 to D1, D1 to T2
R3-D1-T2 (R3 ->|- T2 )

Connect R3 to D2, D2 to T5
R3-D2-T5 ( R3 ->|- T5 )


When "ON", current flows from IG thru relay coil to T5, thru switch to T6, to GRD turning on relay (and thus the fan)
Also current flows from IG to R2 to Lg to T5, thru switch to T6, to GRD turning on Lg (green led)

When in the other on state or "AUTO", the current goes from T5 thru the switch to T4, then to TS (temperature switch).

When the temperature switch grounds due to temperature, the relay is activated turning on the fan. Also Lg gets turned on when the temperature switch grounds.

The green LED (Lg) will be on whenever the fan is on.

When in the "AUTO" state, current will flow from IG to R1 to Ly to T2, then thru the switch to T1 and then to ground, lighting the yellow LED.


When in the center "OFF" position, the Lr (red LED) is on.
(IG-R3-Lr-D3-GRD)

If the switch is in either the "ON" or "AUTO" position, the red LED is turned off because the current takes the easier path to ground
IG-R3-D1-T2-T1-GRD
or
IG-R3-D2-T5-T6-GRD


So red LED means fan off
yellow LED means fan is in automatic mode (can be running or not)
green LED means fan is on


Sounds more complicated than it is............
Author:  Pierre [ Sat Oct 29, 2011 1:53 am ]
Post subject: 
Check out the aftermarket fan controllers if you aren't in the DIY mood - some have A/C input to run the fan continuously when the a/c clutch is on so you could use this as a manual on mode.
Author:  Rick Covalt [ Sat Oct 29, 2011 6:05 am ]
Post subject:  Thanks
Well after reading and re-reaqding I think I follow all the current flows! :shock: But if I close my eyes for 1 second I have to start over! I don't know why It is so difficult for me to "see" things. Thanks Ed.

It may be more fancy than I need. If I just have a red light to let me know it is in the off position it would be fine. If it is on or in auto I really don't need the lights, although they may be cool!

Rick
Author:  Aggressive Ted [ Sun Oct 30, 2011 11:37 am ]
Post subject: 
Rick,

Just use my super simple schematic posted under Engine FAQ, Miscellaneous section, Frequently Asked Questions (FAQ) - Electrical,
Ted's Electric fan schematic.

It is not difficult or complex. I have a simple over-ride switch on my schematic and I use it from time to time in traffic.

Both of the rocker switches have lights in them. The first switch is the arming switch and lights up when on. Between the two switches I have a light that shows when the fan comes on. The third switch light is not hooked up since it is redundant.
Page 1 of 1 All times are UTC-07:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/