The data is just shown, if there's a high cluster installed. Do you have one?

What do you mean with a high cluster?

What is it, and where can I find it?

"High Cluster" means a "Big Bordcomputer".

No Bordcomputer = Nothing
Low Cluster = temp. / speed / consumtion / range
High Cluster = (as low cluster) and: Time 1 / Time 2 / consumtion 2 / time / date / distance / timer / arrival timer ...

If the Nav was build in by bmw you should have the high cluster of corse. but if it was a retrofit, perhaps you have to change the ike, too if you just own a low cluster.

I have no information in the screen.
But the infromation is in the car, things like temperature, range.

It's has been retrofitted indeed. How can I change the ike than?

Is that something which I can do myself, or do I have to go to the dealer for that?

You should ask your BMW Dealer, if you like to do that. The problem needs a little bit more attention. You need a new IKE, some wiring harness, a cooling fluid sensor and some time to install it. Then BMW have to code it to your car.

After that, everything in your navigations system should work (clock, date, arrival time, memo, language, bordcomputer).

And: don't buy a used IKE. It's impossible to code it twice.

Excuse me, i'm going to install a nav-sat retrofit on my E39. I've a low cluster, but I think I keep it on, and use a old MID to view the time and date on the board monitor. Is any possibility to "take" the other data of the low cluster for using in the Bordmonitor computer???

No. The nav expects to receive data from the High IKE. The Low IKE simply does not send the data. So whilst the nav will work, lots of data will be missing (time, date, consumption, etc...)