Outside temp on 2005 Silverado mirror with compass

Aug 01, 2005 3 Replies

With significant temperature swings after a hot day, thunderstorms and cooling overnight, I've noticed that it takes a long time (10 minutes) for the temperature display on the rearview mirror to read the correct outside temperature. The only mention regarding the temperature in the user manual is that sometimes it take "a while" for the temperature reading to adjust, otherwise take it to the dealer. For example, the truck was driven for about 5 minutes when the outside temp was about 70 degrees. It was then parked for about an hour. The temp rose to about



80 degrees, the truck was started, temp on mirror reads 70. As we drove, the temp rose s-l-o-w-l-y, one degree at a time to about 76, then after 10 minutes, jumped to 80 and stabilized there. Is this normal? Or could water have gotten in the sensor's connector?

Thanks for any insight.



Lena



I believe the temp sensor is actually measuring the temp of the windshield glass inner surface. This introduces considerable lag time due to the thermal mass of the glass whether going up or down in temp. One would think that driving at highway speed would reduce the lag time and produce a more accurate reading versus sitting in traffic. The high-speed air blast would tend to swamp out influences such as sun or shade on the windshield. It seems to me the mirror sensor is merely a gimmick that didn't cost much to implement given the electronics package already needed for the compass and auto dimming features.

Randy

I thought the sensor is located behind the front grille, in front of the radiator.

Lena

My 01 K2500 Suburban has similar fluctuations when going through the car wash. When it's 115 (Phoenix) and you go through a 75 degree car wash, the temp stays at 75 and slowly rises over a period of hours to sometimes days. I was told the air temp. sensor is mounted behind the grill. Conversely, while sitting in the car and idling for 20 minutes, the temp. gauge rose from 105 to 115. I assume the engine heat was affecting the grill sensor.

Dr. R in AZ

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