I hope this helps someone. On my 2006 V50, it's the passenger side rear mirror where the sensor is located.
Plastic pry tools, a 13mm socket, T25 torx, a thick paper clip and less than an hour.
Simple "How To" video showing how to easily replace the wing mirror mounted Ambient Temperature Sensor in a Volvo V70 - and with very few tools. Anyone can do this!! Is the same procedure for all of the vehicles on the P2 Platform (S60, S80, V70, XC70, XC90)