2007 Mercedes GL-Class Owner's Manual - Page 260

Controls in detail Driving systems Activating cruise control You can activate the cruise control when the vehicle speed is above 20 mph (30 km/h). In the following cases you cannot activate the cruise control: when you brake when you have set the parking brake when the automatic transmission is set to position P, R, or N if the ESP® is switched off if the ESP® has switched off due to a malfunction Setting current speed Accelerate or decelerate to the desired speed. Briefly lift the cruise control lever in direction of arrow 1 or depress in direction of arrow 2. The current speed is set. Remove your foot from the accelerator pedal. The cruise control is activated. The current set speed appears in the multifunction display for approximately 5 seconds. or Briefly push the cruise control lever in direction of arrow 3 ( page 258). The cruise control is canceled. The last speed set is stored for later use. Canceling cruise control There are several ways to cancel the cruise control: Step on the brake pedal. The cruise control is canceled. The last speed set is stored for later use. i The last stored set speed is deleted when the engine is turned off. i The vehicle speed displayed in the speedometer can briefly vary from the speed setting for the cruise control system. i On uphill grades, the cruise control may not be able to maintain the set speed. Once the grade eases, the set speed will be resumed. On downhill grades, the cruise control maintains the set speed by braking with the vehicle's braking system. In addition, on longer downhill grades the automatic transmission will downshift automatically. 259