mine is opel omega 2002 3.2. i don't know exactly where the sensor is but i can guess.
my car is left side drive and the battery is to the driver side. i made an accident and only damaged part of the left (driver side) bumper, left headlight and left floodlight. that is when i noticed that the outside temperature sensor stoped working.
the sensor should be in the left side to get damaged by the accedent.
when i checked the cable connecting the two (LH & RH) floodlights there were a third plug which was supposed to be connected to a device. i guess it was to the outside temperature sensor.