2007 GMC Yukon Owner's Manual - Page 129

Power Running Boards Your vehicle may have power running boards. These make getting into and out of the vehicle easier. The power running boards activate when either door on the driver's or passenger's side is opened or closed. They automatically extend from beneath the vehicle on the side in which the door has been opened. Once the door is closed, the running boards will automatically move back under the vehicle. The vehicle must be stationary for the running boards to extend or retract. The switch used to disable the power running boards is located on the center console below the climate control system. The running boards cannot be disabled in the extended position. 129