My sensor failed back in April while driving through a blizzard. The ambient air sensor began to climb from in the 30s all the way up to 90. I was using the auto climate in the cabin and when it malfunctioned, it began to blow hard, cold air, fogging up the windows. From then on, the sensor was reading +10-15 more than the reported outside temp.
Brought it in and the dealer noted that the sensor failed. They did replace that and noted that the wiring was fine. The very next day, the issue was still there. I brought it back and they looked at it for a few days and could not find the issue. They wanted me to pick up the car without it being fixed as they had no idea what the issue could be. I mentioned that there may be corrosion on the wiring harness after reading this post and they went and replaced the harness. We are on day 3 of me having it back, and it is all but perfect! (It is +/- 1-2 degrees off on occasion, but that is to be expected).
Thank goodness for the forum!!