Outside temp sensor being a dick

Noticed a few days ago that my dash was showing an outside temp that I was sure was lower than the real temp. It was showing -1 degree, but it was pretty mild that day, prob around 5 degrees. Usually on a cold day it'll creep up by 1 or 2 degrees after a few mins of driving but not this time. Following day it was showing -2, then crept up to -1, again defo not that cold on that day. Today it stuck at 1 degree all day but it was about 5 degrees according to the weather forecast, a fact backed up by my testicles not retreating in to my body.

It's always been accurate up until now.

So quite simply, is it likely that the sensor is gubbed and will need replacing, or something more simple? Perhaps disconnecting the battery to reset the electrics?

It would be best to replace that sensor as it gives readings to the ECU for finer fuelling so as it reads colder you will burn more fuel!!

Have a look at the plugs in mirror and in door ,problem most likely a green pin in a plug

Mine went through a phase of doing this last year. It would read about 0 deg when it was actually about 10 deg. Lasted about a week and it has done it once since, but other than that it seems to have sorted itself out. The temp sensor is the little knob that sits beneath the o/s mirror.

I've not done anything about it as it seems to have rectified itself. One thing that did spring to mind is that maybe the wiring has been chaffed and perhaps there's too much resistance making it read lower (no idea how the resistance values relate to the reading so it's just a guess). Just a hypothesis as I do often fold the mirror in (they are manual folding mirrors).