Caddy overheat light

[Tizer]

VW caddy 2008 engine management light on for overheat even on first start up in a cold morning.
The fan is constantly on but generally runs fine throughout the day.

Occasionally when first starting it will over rev for a second and then settle.

I changed the sensor and it made no difference. Took it to my garage and they changed the same sensor for an official VW one and it made no difference.

They're now stumped and said they would get back to me and didn't.

Anything obvious to look for? Is there only one sensor for this issue as one of the guys ordered a different sensor then I was told it was the wrong one and only had one.

 

[andy1020]

I'd get a good diagnostic scan done, if light is coming on there should be a fault code. A light supposed to be for one thing can be used for other less obvious faults too.
Yes I'd have said temp sensor but if that's been done I'd say wiring / electrical fault next. There's only one temp sensor I know of. I'd try vwaudiforum lots of vw techs on there.