Q: Electrical problems on a 'O4 Volvo S40

Yes I’ve seen that a lot on those things. A lot of them get a fuse box that’s just flat out corroded.

You will have to take the whole thing apart and clean it completely or go to a junkyard and get a used fuse box. A new one can cost a fortune to replace the whole thing.

That being said, if there are a few things that don’t work versus a lot of things that do. You could just rewire those particular things. You can access the fuse box and cut the wires going to the fuse box. For example cutting the wire for the cigarette lighter, and then you can run a wire to your own external fuse and fuse holder. Then you’d run the other end of the wire to the cigarette lighter. Rewiring things that don’t work rather than replacing the whole thing is one way of getting it to work if you don’t want to go through the hassle of replacing the whole unit.

If you don’t feel comfortable doing rewiring work and need assistance with getting this fixed, feel free to contact a certified mechanic who can diagnose your electronic components and fix it accordingly.