Cooling fan switch and light

[Nobby6]

Hi all,

The overheating problems of my S3 now seem to have stopped (fingers crossed!) but for reassurance I'd like to fit an override switch so that I can manually switch the fan on.

Would I be better off using a relay between the fan and the switch (having just replaced the heater fan switch with melted contacts I suspect this would not be a bad thing). I also think that having a light to tell me when the fan is running will probably help (my nerves!) especially when sat in stationery traffic!

Have any of you done this? Does anyone have a wiring diagram?

TIA

Dave

[Wiz]

Fairly standard mod on the griff/chim.

[Bobhon]

Nobby6 said:

Hi all,



Have any of you done this? Does anyone have a wiring diagram?

TIA

Dave

A wiring diagram would be fairly easy with the override switch / relay output going to the fan side of the fan temperature switch.
Then either the standard thermostat switch or the override would turn the fan on.

The tell tale light could connect to the override switch / relay output run up to a bulb holder in the dash, then down to a suitable earth point.

The override switch / relay input would need a suitably sized in line fuse, presuming that you run a new feed out from the battery.

If you need a drawn diagram then PM me and I'll sketch one out, scan it in and send it out to you.

Bob

Edited by Bobhon on Thursday 11th March 22:15

[tvrgit]

Bobhon said:

Nobby6 said:

Hi all,



Have any of you done this? Does anyone have a wiring diagram?

TIA

Dave

A wiring diagram would be fairly easy with the override switch / relay output going to the fan side of the fan temperature switch.
Then either the standard thermostat switch or the override would turn the fan on.

The tell tale light could connect to the override switch / relay output run up to a bulb holder in the dash, then down to a suitable earth point.

The override switch / relay input would need a suitably sized in line fuse, presuming that you run a new feed out from the battery.

If you need a drawn diagram then PM me and I'll sketch one out, scan it in and send it out to you.

Bob

Edited by Bobhon on Thursday 11th March 22:15

I think that the existing thermostatic switch is on the earth side of the fan. not the feed, so taking a fused supply to the fan side of the switch wouldn't work (and would gic=ve a straight short to earth as soon as the thermo switch closed at temperature).

Easy simply way - use a twin-core wire, connect one end to both terminals of the thermo switch, the other ends to your over-ride switch, Now you have two switches in parallel - either can complete the circuit, and no risk of setting the car on fire.

Oh and I wouldn't worry about a tell-tale light, it's simple: switch up = fan on thermo activation, switch down = fan on all the time. It doesn't really matter if you forget to switch it off, and a quick glance confirms if its on.

I don't use mine that often, but it's nice to know it's there.

Edited by tvrgit on Thursday 11th March 22:24

[clarenceboddiger]

tvrgit said:

Bobhon said:

Nobby6 said:

Easy simply way - use a twin-core wire, connect one end to both terminals of the thermo switch, the other ends to your over-ride switch, Now you have two switches in parallel - either can complete the circuit, and no risk of setting the car on fire.

+1
And you would probably struggle to see an illuminated switch even if you fit one, chances are it will be during daytime driving that you need it on.

Edited by clarenceboddiger on Friday 12th March 22:42

[TJC46]

Easy simply way - use a twin-core wire, connect one end to both terminals of the thermo switch, the other ends to your over-ride switch, Now you have two switches in parallel - either can complete the circuit, and no risk of setting the car on fire.

Oh and I wouldn't worry about a tell-tale light, it's simple: switch up = fan on thermo activation, switch down = fan on all the time. It doesn't really matter if you forget to switch it off, and a quick glance confirms if its on.

I don't use mine that often, but it's nice to know it's there.
+ 1 for this. I had it on my S3 and it worked a treat. No need for an illuminated switch.

[Nobby6]

Hi Guys,

Thanks for all the responses... (sorry for the delay in responding, been back home in Scotland for a few days)

Can anybody advise what gauge of wire I should use? And any recommendations for a suitable switch?

Thanks

Dave