[R1916V]

As @RS3100 told you, first disconnect the battery.
Open the right front door. Move the seat to far back to open as much as possible space there. Remove the sill with the inscription "Volvo" on it. It is on clips, just gently pull it up. Now you can turn the carpet back and will see so many connectors there below the right side of the glovebox. Some of them are surrounded by a white plastic "fence", which is easy to open. Turn the carpet as much as possible and near the floor will see other connectors, too. Just behind the glove box there is the CEM module(this one, with many fuses on it) with other connectors on it. Try to disconnect and reconnect all that connectors and maybe spray them with some contact cleaner.
But be careful, connectors with two orange thick "cables" are not cables, they are optical fibers and don't touch them, they are not an electrical wires. Also, they don't like bending and can break internally because they are made of glass. Don't spray them with anything.