Kenlowe fan - is it working?

Morning all

300TDI 90 with a Kenlowe fan fitted. Recently the thermometer has been moving past N (but NOT overheating), especially if I am travelling slowly along an overgrown lane. I would like a manual switch to run the fan but I don't actually know whether it works. I have read some info about the relay failing if it gets wet and I did a fair bit on Salisbury Plains and thru some fords over winter. Without being an electrical wizard how do I get the fan to switch on? I have just replaced the thermostat on the X engineering switch. I have not replaced the relay. Is it possible to (easily) wire up a manual switch to fire the fan if I wish?

Thanks
AJ

Yes doddle, look at relay and see which pin is being used as the signal for the relay (it will be numbered) if not sure post up a pic of the relay and a close up of the wiring at the relay itself.

All you need a is a toggle /rocker switch to supply either power or an earth path to the relay.

A look on youtube on how relays work will certainly help.