Below is a list of light bulb types used in 2008- MERCEDES-BENZ GLK-CLASS lighting system, covering SUV vehicles.
Headlight bulb: low beam - H7 or D1S / high beam - D1S, H7 or H15
Parking light bulb: W5W or H15
Fog light bulb: H11
Front indicator/turn signal bulb: PY21W
Side marker lamp bulb: W5W
Daytime running light bulb: H15
Cornering light bulb: H7
Rear indicator/turn signal bulb: PY21W
Tail light bulb: P21W
Brake light bulb: P21W
Back-up light bulb: W16W or P21W
Rear fog light bulb: P21W
License plate light bulb: W5W
Interior light bulb: W5W or C10W
Boot light bulb: W5W
Entry light bulb: W5W
Footwell light bulb: W5W
Reading light bulb: W5W
Glove compartment light bulb: W5W