Typically, on earlier simpler models with A/C, the thermoswitch would only carry the relay coil current for each of the relays within fan control module (low and full speed) that drive the fan, so tends not to fail often at all. Thin wiring to it more likely to break/ fail than thermoswitch itself.

Can't see any equivalent to this arrangement in citigo diagrams though. For non-A/C citigo it uses just one of its dual switches directly in series with rad fan 12V supply.

Edited 16 August, 202516 Aug by Breezy_Pete

If it's possible it's always best to check a new part works and is the correct item and fitting/fixing as much as you can before you commit to the parts replacement, I've even had the wrong part or label in or on packaging, or just the wrong part sent (or ordered by me in a common moment of confusion and/or lack of glasses).

I'm all for saving time and hassle by ordering low cost parts but then to fit say a switch to find it's untested wiring or connector at fault, far more of a PITA with the thin fragile wiring and connectors on these cars.

Good luck, let us know how you get on (whilst directing your son how to replace the part whilst you drink the tea while it's still warm and eat the last of the biscuits, and if you're my age then have to go for another pee).

It has been a minute...

Finally got access to the car at the weekend.

Successfully got access to the spark plugs by using the air compressor trick to break the seal between the coil pack rubber boot and the spark plug isolator.

Successfully changed the front pads and discs.

Failed miserable in fault finding the cause of the overheating. The car has aircon and so does not have the separate thermoswitch I took a punt on. Oh well...
All fuses (both in the passenger footwell and the engine bay by the battery) appeared to be fine.

Ran out of time and so will have to go again at some point in the future.