Do it yourself, change the tail light assembly on your Volvo S70, the model made between the years 1998 and 2000. You will need an 8 mm socket with a ratchet and an extension and about 15 minutes of your time.
You can start by accessing the trunk of the car. Here you have to remove a cover like the one seen in the image below, that covers the back of the assembly.
After you do it, you will notice an electrical panel with a connector. Pull out that panel and you will have access to the light bulbs. Service them if needed. If not, work to remove the tail light lens.
You can do that very simply, using an 8 mm socket wrench, with a ratchet and an extension. You will have to remove four nuts, similar to the two seen in the picture below, that secure the lens on the body of the car.
So, remove the old assembly, install the new one and secure it with the nuts, reinstall the light bulbs plate and the cover in the trunk. This is all you have to do, if you plan to service the tail light assembly on your Volvo S70, the model produced between the years 1998 and 2000.