Abstract: A low pressure pumping system for power inflating and power bleeding the lumbar support of a vehicular seat including a low pressure air cell mounted in the back support. A two-position pneumatic switch serves to selectively alternately reverse a motor and pump to inflate the air cell to a predetermined capacity of less than 5 p.s.i., and to deflate the air cell through a bleed valve. The two-position pneumatic switch includes a double pole, double throw switch and a slide valve which is positioned open when the air cell is inflated. The motor is sized to stall when the predetermined capacity is attained to prevent over inflation of the air cell.