DIY, change the headlight assembly on your Volvo XC90, manufactured between the years 2003 and 2013. You will not require tools to make this replacement and the process is very simple. Only if you need to service the main light bulbs, you will need a Phillips screwdriver, because one of them has a plastic cover that is held by a Phillips screw. You can start above the headlight you need to replace, by lifting and removing the two tabs seen in the image below. Their purpose is to secure the assembly on the body of the car. Remove them by hand, or if you find it really difficult, use a pair of pliers. Once you do it, you can simply pull out the assembly. In order to remove it completely, unplug the main harness behind it, that powers all the light bulbs (see picture below). Be careful, because it has a red securing tab that you must slide and unlock, first. At this point you have access to all the bulbs. The small ones can be serviced by twisting their sockets counterclockwise. The main bulbs have covers above them. Remove those covers to access and replace the bulbs, if needed (see details in the images below). If not, just reconnect the main harness to the new assembly, insert and align it into the body of the car and in the end, secure it with the metal tabs above. The headlight has also adjusting screws, to tune it correctly. Use them if necessary and that should be it. These are the simple steps you need to follow, if you plan to service the headlight assembly on your Volvo XC90, the model made between the years 2003 and 2013.