Patent ID: 7735516

Claim:
A lift axle control module for a vehicle having a pressurized air supply, a regulator providing a regulated air supply, a lift bladder and a load bladder, the lift axle control module comprising: a housing having a first chamber with a load port connected to the load bladder, and a second chamber with a lift port connected to the lift bladder, the housing also having a supply port connected to the pressurized air supply and a control port selectively connected to the regulated air supply; a first relay valve assembly in the first chamber that connects the load port to the supply port when the control port is connected to the regulated air supply, and vents the load port when the control port is not connected to the regulated air supply; a second relay valve assembly in the second chamber that vents the lift port when the control port is connected to the regulated air supply, and connects the lift port to the supply port when the control port is not connected to the regulated air supply; and further comprising an inlet valve that closes the connection between the supply port and the load bladder when the pressure in the load bladder is greater than the pressure of the regulated air supply.