hi pepole i could really do with some help my 1998 p38 2.5 diesel suspension is down and cannot get it to raise i have the christmas tree lights on so cannot use rocker switch i have shortend out the relay to get the pump to work and left it running and checked the tank unerneath seems to have alot of air in the tank but will not raise is there some type of activation to raise it or will it self raise when the tank is full i.e valve ect many thanks gaz from telford