Originally Posted by john4231618

The aux heater heats air that is routed directly into the interior. I DOES NOT preheat the coolant.
On early UK delivery X5s this heater is fitted, but innactive. On all facelift X5s, it is active.
I'm not sure when the changeover was made.
Mine was activated in 2003 by the dealer after no small struggle because BMW UK said it was illegal to use it in UK. Their reason was that it could pollute the air in an enclosed garage. True.
However, I pointed out to them that LandRover used axactly the same heater, and it was active. BMW then gave the dealer details of how to make it work, and it did!
I guess that this followed through to all UK delivery X5s being delivered with a fully working preheater.
The aux heater cuts out when the temperature in the car is about 15deg.
You'll have to ask a dealer to reprogramme the car to make the heater work if it does not switch on automatically when you start the car at temps below +15deg. This reprogramme also activated the screen controls which prior to this permitted only the venilation mode, not aux heat......in fact, I guess that you can tell if the aux heater programme permits its operation by looking at the options on the screen. If no AUX heat offered, its not going to work.
The remote is a separate issue. It starts up the heater from a distance. However, simply installing this option will not neccessarily make the heater work automatically when it's cold in the car, nor allow you to programe the heater from the screen
If yourt aux heater is not active, it's well worth getting it sorted.
The remote is ok, as is programming the aux heater to start on a timer before you reach it, but in low temperatures, I'm in the European mountains all winter, running the engine for 5 mins before seting off is just as effective, and does not deplete the battery.
Phew