It happened to me, about six months ago. It turned out it was the gear of the actuator motor, on the transfer case. Opened it up, turned the gear 180 degrees put it back on, everything was fine. Then a couple of months later I got all lights again. This time I went under the car and noticed that the connector where some wires go, on the actuator motor was broken and the wires made intermittent contact. I used a tie wrap to secure the wires on the connector, and everything is OK since then.

__________________
John Caradimas
2005 X5 3.0lt diesel
Facelift, Sport packet