My sensor has been been flaky of late, sitting in my driveway, turned car on and it was reading 135° most of the time it reads normal ± a couple of degrees. I noticed that immediately after washing my car, it would read considerably lower, and, over time would eventually climb back to normal. Other day, outside temp was 108°, washed my car, and soon after it was reading 86°. Took in in to the dealer today, and they replaced the sensor, but, they also told me that to read significantly lower after car washing was "normal" and that it should correct itself by about 16° per hour. Since this reading has a direct impact on cooling of air conditioning, I wonder about this?

 

i wonder if mine is going out. it read 86 when it was over 100 the other day.

 

It reads the ambient air temperature in the nose of the car right in front of the radiator. It will read most accurately when the car is moving (exchanging air). It will read very high if the car is driven, and then parked for a while where the radiator will heat the air in the nose. Water evaporating (like after a wash) will lower the temp also. Only trust the temp either when the car hasn't been driven, washed, etc. for a long time and it's not in direct sun, or you've been driving at a decent speed for a minute or two.

 

mine reads about 10+ higher than normal

 

Glad I'm not the only one, mine ****s up a lot too. Usually reads lower than it is outside.

 

There is a temp sensor inside the car (not outside) that controls the a/c.

You're getting a high reading when parked on pavement due to the reflective heat adding to the air temp (especially in LV). I frequently notice that the outside temp drops 10+ degrees within a few minutes after leaving a parking lot and getting on the freeway.

 

Actually, the ambient temp also effects the amount of cooling, and yep, but the time mine read 135°, had been parked in my garage all nite and I had just started it for the 1st time. Even parked in outside lots for several hours, it seldom reads much higher than OAT and seldom drops more than a 1° or 2° after driving off, or, until its washed. Regardless, they changed my sensor today, washed my car, and it was reading more than 10° below OAT.