Cooling fan on Seight adding a thermostatic switch

[Badger56]

Hi all,

I've searched the forums to no avail, trying to add a thermostatic switch to my Seight as it just has a manual one at the moment. I have the following : 

 

http://www.carbuildersolutions.com/uk/adjustable-fan-controller-thermostat

 

and I'm not sure which wire goes where, from the fan I have a red & a black wire, finding a suitable connection to disconnect I've found that with the switch on they are both live, I assume there is a relay involved somewhere and I've tested the circuit  before this i.e. on the fan side in the engine bay.

 

I could do this by trial & error but if anyone has a more scientific method I'd be grateful for a pointer.

 

By the way, I can highly recommend "car builder solutions" as a web site, they appear to have anything you could possibly want.

Cheers

Dave

 

[alfie_fraser]

What radiator do you have? I have just replaced my thermostatic switch which is integral can dig some photos out to help you find it if you have a standard polo rad.....

[Badger56]

Thanks, its not a standard rad but a thicker high capacity one as far as I know, nowhere to put a sender. I'm just a bit confused about the "red & black" wire as they don't seem to agree with any wiring diagram I've seen. I think I'll have to dig a bit deeper with the circuit tester :-)

Cheers

Dave

[SootySport]

If you have an early Seight I doubt you will have a relay.  To prove it, ignition on, disconnect the two wires on the fan and see if you have 12v. on either wire, probably the red one.

Then clip your voltmeter to  the black wire, should have nothing.   if so just connect your new fan switch as in the CBS diagram.

[Badger56]

If you have an early Seight I doubt you will have a relay.  To prove it, ignition on, disconnect the two wires on the fan and see if you have 12v. on either wire, probably the red one.

Then clip your voltmeter to  the black wire, should have nothing.   if so just connect your new fan switch as in the CBS diagram.

Thanks, I'll give that a go at the weekend, but to be clear you think "C" & "2" should be connected to the red wire & black left as it is? That's what I'm coming to think, I also guess that the switch will need to be left in the on position for the thermostatic switch to operate but I could always bypass that later I supose.

Thanks again

Dave 

[SootySport]

Red to 2   and black to C.   Should be that simple.   The fan control knob to be turned to whatever temperature you want the fan to kick in.

[Badger56]

Just for closure, sorted now, the thermostatic switch "breaks" the red wire, the manual switch has to be on but works fine.

[SootySport]

That doesn't sound right.   The thermostatic switch should switch the fan on at selected temperature without the manual switch operated, so I guess the fan is running constantly now.     You need to find help with it locally.   

[Dave Eastwood (Gadgetman) - Club Chairman]

No, the old switch is just being used as a power source for the new thermostatic switch, which operates normally, provided the original switch is on.

I would suggest bypassing the old switch though, at your earliest convenience - it's way too easy for it to get turned off and you not notice till the engine starts to overheat.

[Badger56]

No, the old switch is just being used as a power source for the new thermostatic switch, which operates normally, provided the original switch is on.

I would suggest bypassing the old switch though, at your earliest convenience - it's way too easy for it to get turned off and you not notice till the engine starts to overheat.

Thats correct Dave & thanks, I intend to bypass the switch and maybe use it as an override later on but thought I'd let it settle before I do any more, its a good job I did by the way, as not long after I sorted this out a connection came off resulting in a hot engine, I was able to reconnect the original switch and get the fan on which avoided disaster. All working well now though so intend to bypass the switch soon.