Oldsmobile/Buick: I have a 89 buick Lesabre...., external temp sensor, electrical gremlins

Question
I have a 89 buick Lesabre. The Ext. temp reading goes from about 85 to 145 degrees while the car is idling. I know it measures the outside temp. but I was wondering if the probe sensor was old or something else. When I turn on the air after a minute it starts to go back down. I don't know if the engine is too hot, the dummy light doesn't come on or any other indications. Could you tell me where the external temp. sensor is located? Could engine heat also up the reading?  Thank You

Answer
Hi Ronald,
External temp gauges are definitely not a specialty of mine.
Plus troubleshooting electrical gremlins is quite difficult. There are so many factors, and so many circuits! To be sure, you will have to take the car in to the shop, let them put it on the computer and read what your car is doing. What does concern me is the reading fluctuating once the a/c is turned on. That is electrical. Could either be a fuse link is going bad, a short or even worse the on board computer is dieing a slow death. Yes, your cars computer can effect everything. I've known many owners of older cars who's on board computer went bad with age and had to be replaced. If so, that will set you back about $500.00 not installed. Many go to the junkyards and get one for $100.00 or so. The computer is on the extreme side and you may not even have to go that route. Take the car in for a diagnostic and tell them exactly what this gauge is doing for sure, from there they can read the appropriate codes. Hope this helps! Ray