Here' show to create more troubles for yourself.

Driver side mirror got knocked by some idiot in the parking area. Not a problem, will just open it and re-attach. Yeah right!!!

Re-attached the mirror (pulled out of the screws) put the whole lot back again, now the temperature is showing some nice straight lines, the little red light next to the door lock pin is not working and the mirror adjustment is not working on the mirror.:bang:

Guess I will have to strip the lot again.

Before stripping it again try disconnecting and reconnecting the doors wiring loom at the plug where it goes into the A pillar. This often sorts this occasional issue out for me

Just for the record, after stripping the whole door, again, and dropping one of the screws inside the door (F&^%) found all to be perfect on the inside with no loose cables etc. :bang:

Then the penny dropped, pull fuse F53 wait 10sec. put back sensor works perfectly.

Anyway I am now the door card remove expert on this site!!

Is the sensor inside mirror? That would explain why it shows even more ridiculous temperatures after being parked with drivers side towards the sun.

It's under the mirror