Pontiac Repair: Temperature reading Pontiac Montana, pontiac montana, gm dealer

Question
Hi Todd.
Lately, in the last month or so, I have been subjected to more traffic, and when driving very slowly, or even idling, the temperature read out on the outside temperature on my 2007 Montana creeps up.  This afternoon, in heavy traffic, the actual temperature outside was around 15C, and at one point, my van display got up to 39C.  I know once I start driving again, or speed up, it reads properly, but it never used to do this.  Perhaps the sensor is dirty, or blocked?  I don't even know where to start looking for it, and was hoping you could tell me.
Thank you very much for your time.

Answer
Hi Mark:

sounds like the ambient temp. sensor is skewed high. pretty common issue on those vans. the sensor is mounted under the hood in front of the radiator. you can get it at any GM dealer all the vehicles pretty much use the same sensor. the parts guys can show you a picture as to where it is on your van. good luck :-)