What is this wire/sensor?

[Ben Lessani]

As title, found it snapped, will solder it back together, but wondering what it was?

[rubjonny]

fan after-run switch

[Ben Lessani]

:super dooper confused:

this wire has been broke for yonks by the looks of things. but after i stop the engine - the fan usually happily runs on for 10s or so before cutting off? not to question you, but you 100% sure?

[rubjonny]

I am, this is a seperate thing to the one in the radiator, which can and does run the fan after the engine is off, because it has permanent 12v. The after run triggers the fan if the engine bay temps climb too high after the car has switched off, its supposed to help reduce fuel vapourisation problems.  Also if you earth that wire it should trigger the fan, so if it has been touching any metal then that could also explain why your fan is coming on.  I think there is a timed relay that controls it?

[Mew]

Hmm, swear mine didn't have one of these

[rubjonny]

yeah its not fitted to all cars as std, my digi 8v and kr 16v lumps didnt have one but the abf lump i have did