Yes, you pull it out to raise the car. You pull it once, it raies the car like 4" and you are not supposed to drive any faster than 50mph that way. You pull it once more (farther out) and it locks the car in the raised position for service. If you ever put your car on a lift, or take it in for service you need to make sure they know that the knob needs to be all the way out. If you dont, the weight of the wheels will pull down on your hydromat struts, and push all the expensive oil out of your system. So, pull once to raise your car to clear snow or speedbumps, and pull it out all the way for service. Before going into service, i always leave the knob pushed all the way in, wait for the car to rise to normal height, then pull once, wait for it to rise to the "high" position, then wait, then pull it all the way, and wait again before putting it on the lift. Better safe than needing 3 liters of $20/L oil.
Hans