thermo fan switches

[FC 304 wannabe]

hi guys,
I've converted my fc motor to a vn 304 5L and need to run thermo fans.
what would be the best switch to use ?
I'm chasing something auto that cuts in at say 85 degrees ....

thanks,
Shannon.

[FCRB26]

http://www.ebay.com.au/itm/THERMO-FAN-SWITCH-DAVIES-CRAIG-ADJUSTABLE-40-100-DEG-C-12V-24V-0401-/290759229533?pt=AU_Car_Parts_Accessories&hash=item43b299c05d

[colt]

I've got one on my grey that cuts in at 85 degs. It screws into the thermostat hole that would take a standard switch. With an adaptor. I just got it at an auto parts store. Works a treat.

Colin.

Wouldn't a 304 have one fitted somewhere?

[john253a]

i used the davies craig switch, as i used there fan as well,
there fans are more designed to push then pull, but still work well in both directions,

i also modded this as well (not needed if you dont want want),
the signal wire from the sender to the really was cut, and 2 core 1.13 was run up to the dash with a on/off/on switch
the switch has 3 terminals
1 with 12v+ live from ignition
1 from sender
1 back to relay

the on wire back to really i also added a led light to tell me when it was on,
this way i could either leave it on auto on/off through the sender, or manual and have it on permanently, (if i was being silly in the car)

http://www.daviescraig.com.au/Controller___Switches-ELECTRONIC_THERMAL_SWITCH__12V_ONLY___PART_No__0402-details.aspx

[john253a]

i must be a slow typer,
no replies when i started, now 2 bet me to it

[FCRB26]

Gotta be quick  ;D

[brett_f]

I had a bloke modify the computer chip to make the thermos come on and off at a certain temp. I believe he did this using the area of the computer that switches the thermos on and off through the air cond.
Brett

[FC 304 wannabe]

Thanks Guys,

I tried to wire a relay to switch using the 304 ECU but it didn't work. I guess it may not be getting other information required.....

Thanks for the info, I thinks i'll just get the davis craig 0401 sensor.
I've wired the relay so the fans will start when the sense wire is grounded....so if i could get a switch that grounds or closes when activated at say 70 -85 degrees thats all I need.
I also don't want to use the same hole as the water temp guage sensor, so ill have to plumb the sensor in through the top radiator hose
:)
Shannon.

[Ed]

Shannon,

I know the reply is late, however with the ECU, you can hook it up via the AC condenser fan.

I forget the exact details but you give the ECU the AC on voltage. and the fans will kick in automatically at 85.

If you're still interested I will look up the exact circuit and pin details.

Cheers

Ed

[Ed]

OK found the info..

the condenser fan repay is controlled by wire into ECU pin C1.. it is an Earth control.

therefore you wire your fan to a relay with the earth wire to C1.

C1 will trigger when coolant temp exceeds 107°C
or
AC request signal is received and Vehicle speed is less than 55kmh (must have a VSS)
or
in diagnostic mode
OR
when Code 14 or 15 is triggered.


to give your ECU an AC request signal, provide voltage to pin B8.


If you do this you will have ECU controlled thermo fans.. with an optional manual over ride if you switch the voltage to B8.

the default without switch will be ON when travelling under 55kmh.

Cheers

Ed