Headlights Switch Off When Car Stops

[Malcolm]

I have just experienced tonight a strange phenomenum on my E53 X5 3.0d. When I started the car and switched on the headlights (manual) they would not come on. The sidelights were OK but the foglights would also not come on. When I started moving the headlights came on. Whenever I stopped the headlights would go off and come back on again as soon as I started moving. This went on for about 30 mins and then it disappered and the headlights then stayed on all the time. Does anyone know anything about this as this could be quite a safety problem when manouvering in a dark car park.