Hi, switch the lights on, and then put he card, do the lights move down then up?, this is called the 'signature' movement, if not then this could indicate a computer/sensor problem, if they do then check the linkages as mentioned before on the front and rear suspension.
Hope this helps...
My Espace is suffering from no 'signature movement', you say this could be a computer sensor problem, is there anyway of checking the sensors without hooking the car up for a diagnostic check? i.e. where is the sensor located?