Hi, I am new to the site and not very mechanically inclined with cars. Single mom with 3 kids on a budget....can't afford car repairs!! I have a 2006 Pontiac Grand Prix GXP V8 - 34,000 miles. Lately the thermometer reading on the dash goes from 79 degrees F to "0C" reading to -25 degree F. It's all over the place. Plus my air conditioner will initially come on, then the temp gauge starts going crazy and the air turns warm. The air force is good, but it turns to warm air. Help!

You will want to check the outside air temperature sensor. GM typically likes to stick them in the nose of the car, behind the front grille. If that unit is bad, or if there is an issue with the wiring going to the unit, it will cause the EXACT symptoms you are describing.

_________________
~Randall~


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place

The sensor tells the climate control what the outside temp is, so if it think's it 0* out, it's gonna blow hot air to get it to whatever you want it to be. If you find the sensor, unplug it and see if it's your issue. Not sure where exactly it is, but they're usually by the hood latch mechanism under the hood at the front.

_________________
Bye Bye:

RIP sandrock

Your temperature sensor might look like this attached to a support in front of the radiator.

When the temperature outside is sensed as below 50 degrees, the AC compressor is turned off. So that's why you lose your AC when the sensor goes crazy and thinks it's cold outside. When you find the sensor, disconnect the connector and reconnect it to try to get a good connection. Hope that's where the problem is.

This sensor is for a Grand Prix GTP $13 at Advance Auto Parts.