if they for the astra you go in boot compartment and peel back liner behind the light and you should see two white screws. undo these and the whole unit should pull off the bodywork. un clip the electrics and remove the light cluster. on the back of the cluster is 4 screws. undo them and take the back off the cluster. you should see the 5 bulbs. replace the one needed and re assemblelight making sure seal goes back correctly. dont drop white screws into bumper!!!