I'm guess you have an air ride equipped expy.... since mine doesn't have check suspension light... But i wouldn't think that it would set off the light since it is pre-loading the bars to act like your lifting the front end to get more clearance... I thought the light is only in regards to the electrical part of the air ride... and if you crank the torsion bars you wont need an alignment as long as you measure the sides of expy and turn bolts equal to keep truck level... or if light comes on try doing the TT (Torsion Twist) and reset the computer and see what happens