Electric Fan operation

[John E]

The previous owner (Plonker) of my crossflow had the cooling fan wired up via the heated screen switch so it would only work manually. I've now wired it correctly from the loom and wonder about the following,

 

1) On a crossflow what is the preferable fan cut in temperature.

 

2) In the event of this failing is it wise to have a simple on/off switch to overide the automatic system.

 

3) If the answer to 2 is yes then what is the best way to wire it up? My thoughts would be to take a permanent positive via a fuse to a switch and then break into the feed after the thermo switch. Any thoughts?

 

On a separate subject what is the function of the resistor on the battery cut off switch. Mine has just fallen off.

[mark.hall]

Not an electrics expert, but I can tell you that the resistor on the battery cut off switch prevents you from frying your alternator, should you use it to turn off the engine. If you use your cut off instead of a "normal" ignition switch, then wire it back in. If it's just used as an anti-theft/piece of mind device, and you don't ever envisage using it in to turn off the engine when running, then I wouldn't worry about it, as you will not be sending high current through to the alternator/diode pack.

[CHRIS CLARK]

John.

 

I can't give you the cut-in temp. of a X/F as I have a 'K', but out of interest I have fitted a 'Kenlowe' thermostatic switch (available as a spare part) wired to the std. elec. fan so I can have the cut-in temp. variable from 60* to 130*. It also has an overide option so you can have it running whenever you want.

 

PS. My problem was overcooling!!!!

[Graham Sewell]

The easiest way to get a manual fan switch is to use a relay near the 'thermo-switch'. The best way I found to wire this is to take the permanent live from the thermo-switch and then route a low current wire to ground via a switch on the dash. The worst consequence of this would be that the fn runs continuously.

 

This permanent live is then continued on to the switching circuit of the relay and the switched current returned to the similar connector on the thermoswitch. All of this can be achieved with piggy-back connectors. The wires for the live feed and the switched return must be capable of handling 10A (15A peak for a couple of seconds while the fan starts with a steady state of about 8A).

 

This setup has worked for me for about 4 years (since I got caught in traffic of a hot summer night and had to turn the heater on full blast to prevent a major over-heat).

 

Cheers,

 

Graham

[John E]

Thanks guys. Switch should cut in at about 94/96 and cut out at about 90.

 

The wiring is going to be this weekends project. Thanks for your help.biggrin.gif

[CHRIS CLARK]

John.

 

That is the (gauge) figure for cut-in that I have set the 'K' to. Now runs at an indicated 78* normally!