2004 Bravada Digital Thermometer problem

[starver]

The digital thermometer on my 2004 Bravada (28,000 miles) is malfunctioning, reading outside temp. First it was slow to display the temperature, staying on 50 for several minutes before reading the correct temperature.

The display is at the climate controls, not on the rear view mirror.

Now it almost always stays on 50. It will erratically scroll up or down 20 or 30 degrees but returns to 50. It may or may not do this several times during a half hour drive. However, it does not display the correct temp. at all.

I am thinking its a faulty sensor. I don't know where it reads the temp. from.

Any ideas.