Are these temp sensors for auto climate control or what?

 

The forward vent is where a mic should be for hands free phoning if system is installed. The rear vent is for the motion sensor/alarm system, though I'm not 100% sure.
The mini is usually wired for all options whether you purchase them or not.

 

Does your MIN have the factory alarm? It would have a red light on the end of the wiper stalk. I believe the vents are for the ultrasonic motion detecter.
But I may be wrong.

 

No, I don't have the alarm but wouldn't they still install the vent looking thing but just not add the actual electronics.

 

Vent is for the motion sensor -- where it would go whether you have the alarm option or not.

 

I understand that the battery in the mostion sensor has to be changed periodically. Does anyone know how to open the vented box on the rear ceiling?

 

If the alarm is the same as BMW's (which have the same assembly in the headliner), then there is no need to access anything such as a battery.