Outside Temperature display
 

I don't have an outside temperature display as I have seen on the displays of other DB9's. Mine is a 2005 should there be one?

Could be 1 of 2 issues, either the ambient temp sensor is bad and not functioning, which I highly doubt becasue you would also be complaining of the battery not charging..The other possible which is suspect, you have an early model that had a known issue with the need for a software update...go to the dealer, they'll flash the car and I'm sure you will be good to go after that...believe it was the CCM that required the updated flash

Can the outside temp display be change to a digital clock display (in the instrument read-out)? I've seen this on the 2014 vehicles.

Probably not your problem but kind of related: I was getting false readings from my outside temp display. Turns out a mud wasp or something like that had built a nest inside the sensor. Cleaned it out and now it's reading properly.

No..

The display for the ambient temp will be in the center stack...

On the newer cars with Beru for TPMS, yes there is ambient temp and a clock in the cluster also.. To have this on an older car though, might work if you had a good engineering contact at HQ in Gaydon to reprogram the CEM and cluster to work with an older model........which would be unlikely ..LOL ..But that would be your only possible way that I see>

How does the ATS cause the battery not to charge?

PCM uses ambient temp to figure out the possible battery temp(don't forget battery is in car..ever seen a battery explode?), if the PCM thinks the battery might be cooking if charged at 14V(large amount of fumes and maybe explode), the PCM will pull back charging voltage to 12V..at 12V your battery is not going to charge, battery is going to slowly drain with the vehicle running and all those nice accessories loading up

It can stop the convert top from working, trans from shifting, and of course screw the hvac system entirely..etc..The ambient temp sensor controls EVERYTHING!!!! :D

Finally got to the dealer and had the programming done. I now have an outside temperature display. The strange thing is when I turn the a/c to low the outside display reads anywhere between 18 and 25 degrees? Any ideas

Learn the Metric system, your in Celsius.

If you want to convert the temp to F, key in turned off, hold down radio presets 4+5 together, still holding presets turn on the key to position II..temp should change from C to F or vise versa if F to C with in 5 seconds

Let me clarify. The temperature is in Fahrenheit. The number changes to a number that doesn't coincide with Celsius. I am familiar with both units of measure. The change only happens when I turn the temperature setting to low. If I set the temperature to 60 or higher it reads correctly.