Land Rover Repair: Air Compressor, air leaks, bubble solution

Question
Hi there
Have a '51' plate discovery.  When i turn the ignition off, the compressor keeps running. (rear air bags only) The only way i can stop it is by disconnecting the battery. When i re-connect the battery it carries on.  What could this be?
Cheers     Liam Reilly

Answer
The compressor stays energized for up to 1.5 hours after the vehicle is switched off.  The compressor can be activated by a stuck relay (under the hood in the main fusebox) or an air leak in the suspension system.  I would first check the relay by swapping it out with another from your car.    If this is not the problem, check for air leaks with a spray bottle and a bubble solution  (such as washing up liquid), checking each air bag, the valve body and reservoir.  Spray solution on wach and if it bubbles up there is a leak.  Lastly, it could be the suspension ECU.