One problem related to headlight switch has been reported for the 2004 BMW 325. The most recently reported issues are listed below.
Bought my BMW brand new from the dealership and after about 5 years of having my car, I noticed that my xenon headlights were not shining as bright as they usually did. Had to use the high beams at night in order to see while driving. After having only one headlight replaced due to cost. Have always gotten a dash warning light that indicates no high beams. Had lights checked out and was told that the high beam was not getting power in the light that was replaced despite the fact that this was a brand new headlight with wiring harness. After having other light checked, it was found that all the wires in the light had dry rotted and all the protective covering had just about come off the wires obviously due to the heat that is generated by the xenon light. Contacted BMW north America regarding the matter and got no resolution despite the fact that there is clearing a defeat in the headlights and it's wiring. Have had the igniter, ballast and control box checked by switching it out with the new headlight parts and the unreplaced headlight still illuminated dim as it did before switching out the part.