Opel ASTRA Owner's Manual page 210

208 Vehicle care
Light assembly in the tailgate
1. Release the cover in the tailgate
and remove it.
2. Unscrew the plastic securing nut
by hand.
3. Carefully withdraw the light
assembly from the recesses and
remove.
4. Detach the plug from the light
assembly.
5. Press the three retaining lugs and
remove the bulb carrier from the
light assembly.