V8V external temp sensor replace DIY ?

[petesv8v]

My external temp sensor seems to have become a bit eratic and for instance today ran car for 20 miles parked for 2 hours in the open and on restarting display read 26C and took quite a bit of time to come to ambient temp.
Anyone know if replacement is a DIY proposition or off to dealer?

[petesv8v]

Thank you Tony - wow something easy and straightforward to fix on an Aston
Cheers Pete