1999 Regal Outside Temp

My Dad's Regal never reads the outside temperature correctly. Would this be related to bad solder joints in the control panel, or would it more likely be a sensor issue?

Don't feel bad. None of mine are that accurate either. How far is it off?

Don't feel bad. None of mine are that accurate either. How far is it off?

My 99 Regal is dead on, and his seems to be off mostly during the winter, don't read below the freezing mark.

The ambient air temp sensor circuit is fairly easy to troubleshoot and check. At ignition to ON and climate control in AUTO, check for 4.5-5.5 volts DC at Pin A input (LT GRN/BLACK wire) at the sensor electrical connector. Pin B (Yellow wire) is ground. The way the sensor works is internal resistance decreases as temperature increases and vice versa. You can check the sensor out of the circuit with a digital multimeter. Plus you could use the one in your Regal as a calibration standard or comparison. If the sensor checks out then it is either a wiring problem back to the climate control head unit or the head unit itself.

My Dad's Regal never reads the outside temperature correctly. Would this be related to bad solder joints in the control panel, or would it more likely be a sensor issue?

The ambient air sensor is probably bad, which is a common failure. It is fastened to a plastic air dam behind the radiator, and really easy to get at/replace. IIRC it is only visible if you look up from underneath the car though. It is GM p/n 10248414 and costs ~$10 from the dealership.

I had to replace it in my wife's old car (1999 Olds Intrigue). The climate control unit said the outside temp was 34*F in the middle of summer and would not allow the A/C to come on because the ambient air temp was bad and indicating a false reading. The A/C compressor isn't supposed to engage if that temp reading is below a certain temp (usually 40*F).

While cleaning ABS connectors I cleaned the connector (contact cleaner) to the temp sensor on my 2000 Regal. After doing this the digital temp indicated correctly. Relatively simple to reach the sensor from above in front of radiator. Worth a try...