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Thought I'd install an override switch for electric fan, in case of sensor failure & fan failed to switch on. Car has been fitted with Revotec unit with adjustable sensor, by previous owner. Car had previously been installed with a Kenlowe unit & unused override switch was still on dashboard.
Lo & behold the day before I planned to wire in the switch the sensor failed, unfortunately in the closed/on position so fan wouldn't stop, had to unplug relay.
Fan wiring isn't ignition controlled so fan would still run for a minute or so to remove residual heat. Definitely not relay at fault as I can feel it clicking in & out when I unplug it & plug it back in + power circuit tests open with multimeter when relay is unplugged.
I have receipt from previous owners purchase of Revotec equipment. 4 years ago, but car had been off road until I purchased it due to previous owners ill health. So car has done less than 500 miles since Revotec fitting & controller has failed.
I've had to order a new fan controller.
Does anybody have any experience of the reliability of these units, less than 500 miles use in 4 years does not instill confidence in it. Maybe should've ordered alternative controller, Revotec unit isn't exactly cheap.

I recently changed to one of these radiator fan switches on my 7V8. https://www.ebay.co.uk/itm/184422095530 ...

It uses a fixed temperature on / off switch which replaced the previous capillary tube item which caused the hose to weep under the hose clamp every few months.

It was easy to fit and the operating temperatures are a given instead of twiddling a knob and measuring with an infrared gun. If the temperature switch were to fail, then they’re freely available from motor factors as they’re fitted to moderns.

It’s wired through an ignition switched supply operating a relay so it doesn’t run on when parked unless it’s intentional and I’m sitting in it.

Thanks for reply. I've looked at that same one & think I may end up going down that route if replacement Revotec one fails again in a relatively short time.
Did you use the 85° one shown in the link, I'd have thought that was a bit low as car thermostat is rated at 82°. I have a 7V8 as well & would have thought 95° on switch would be the best option according to eBay vendors description for use.
New Revotec unit due to arrive tomorrow (Tuesday) according to DHL

Yes, I bought the 95c switch on 85c switch off to work with the 82c thermostat on my V8. With the aluminium radiator the electric fan’s only activated in stop / start traffic.

I have another aluminium insert in the top hose with a small diameter bleed hose to the standard 7 header tank. This works well with a jiggle pin thermostat (pin at the top) as it prevents air locks especially when changing the coolant.

Cheers

Which is the neatest solution Stevie……

My radiator has a welded boss to take a radiator fan switch. However, a few weeks before fitting the new radiator I’d cut a new top hose to take the 2 aluminium inserts. Doh!

New controller now installed & everything working as it should in that department. I've bookmarked the fixed range one (just in case)