Don't know if this has been covered already but here's a Quick fix post for those suffering water in the boot lid,
Remove bulb cover inside boot lid
Remove plug(mine is wrecked but wires and heat shrink on route )
Use a 10mm socket to remove the light retaining clip
Now clean the foam seal around the light and the bodywork on the boot lid
Use plastic friendly silicone sealer (this ones £5 from halfords) and put a bead of silicone around the foam seal on the light unit
Now just reinstall and jobs done
....no more water in the boot lid wrecking your lights
Remove bulb cover inside boot lid
Remove plug(mine is wrecked but wires and heat shrink on route )
Use a 10mm socket to remove the light retaining clip
Now clean the foam seal around the light and the bodywork on the boot lid
Use plastic friendly silicone sealer (this ones £5 from halfords) and put a bead of silicone around the foam seal on the light unit
Now just reinstall and jobs done
....no more water in the boot lid wrecking your lights