Volvo 850 Ambient Temperature Reading Bad, Goes up and down.
 

Ok, I don't know where to go from here. I have tried what I know and can't find answers in the manual.

My ambient temperature gauge is wacky. I replaced the sensor in the spoiler with another used one and it's still wacky, doing the same thing. It will display any temp and sometimes go LO. Today it started at -20 and slowly raised to 73 (it was suppose to be 76 outside). Then The next time I started it started at 17 and when I looked at it 5 minutes later it was up to 73. I can be driving along and watch it drop to whatever.