Temperature on OBC and AC

Last night I was testing the top speed in my newly aquired 99 528i. At some point between 110 and 130 my temp guage on the dash computer flashed and started showing -40 degrees. This morning I went out to run some errands. It was still showing -40 degrees. After about a half hour of driving it slowly starts ticking closer to 0 degrees. It got to about -33 and then I had to turn the car off to go into a store. Each time later in the day when I started the car up after various errands it was always at -40 and never moved. I also have no AC since last night. I think that maybe due the fact that the car thinks its -40 degrees. Maybe its some sort of system safety check. Who would use their AC in -40 degree weather anyway? I would love any insight someone might have on this!

Bad or missing ambient temp sensor. Cone shaped and located right under right side of front bumper. -40 is the default temp for a missing or bad temp sensor. Look to see if it has been taken out by a curb or is just plain missing. No A/C because of this. Fix this problem and you will have A/C again, I promise.