Alright so my brother got his first car Volvo s40 1.9t 86k original awesome right? Well currently I'm having an issue with the low beams, my drivers side low beam worked but my passenger didnt. Ok easy fix replaced it for him. Turned on the car now its vise versa drivers off passenger works. I checked the fuses and they look fine, even swapped em and the lights to make sure. Was thinking about just wiring them on the same line at this point but figured I would ask .

 

This is a somewhat common problem with the Central Electronic Module. You can either replace it with a new one ($$$) or a used one ($$) or desolder/resolder the broken parts yourself ($).

https://volvoforums.com/forum/volvo-...w-beams-68391/

 

Just had the same problem with my S40. The fix was to replace the Central Electronic Module as Hudini said. My shop was able to find it from somewhere in Canada for $250. I wasn't in a hurry to get it fixed so they spent sometime searching for it. New part cheapest they could find in the states was $400. You can find it cheaper, it just takes time searching.