I've got an intermittent problem with the ride-height system. Occasionally the dashboard indicator comes on steady, and the manual controls are disabled. Switching off the ignition resets it, for a while. I can sometimes cause this event as follows: Put a 50kilo load in the boot. With the engine running, starting with the ride height on low, manual or auto setting, press the up button. After between one and a half and two minutes the indicator will come on. If it doesn't, press UP again and it is likely to show the fault. It does this even while parked. Once it has happened, it occurs every time the height is increased. Driving around and trying again may not show the problem. At other times, it will change height correctly, although it takes 30 to 60 seconds per step, and always moves the back of the car up first. Going down takes about 20 seconds per step. I saw a review somewhere which said it changed in 3 seconds - can anyone confirm this? With the load in the boot, driving over bumpy roads and speed bumps doesn't trigger the fault, at any ride height. With a bigger load in the car, say 300 kilos, it will drive for perhaps 20 miles then put the indicator on. In thinking low air pressure, leaking control valve, leaking pipe (latter unlikely). Any thoughts? Is the compressor electric or engine driven?