I tried this a long while back when I wanted to mess with the outside temp sensor to check if it really worked. My truck was parked in my garage and ambient temp was about 70 according to first reading. I popped the hood, located the sensor (in front of radiator attached to support beam - to left of horns while facing truck). I took a can of compressed air, turned it upside down and gave it a quick blast. I turned the key to the ON position and the temp gauge read something like 62.