Three problems related to fog light switch have been reported for the 2003 BMW 3 Series. The most recently reported issues are listed below.
The zkw xenon headlights have a flaw in the plastic projector housing. The housing gets too hot and melts and the light output is severely restricted. This happens to 100% of the headlights made by this manufacturer and is a safety issue. The reflective coating on the headlights melts and the light can no longer be projected out correctly. The fog lights are now brighter then the headlights. The vehicle can no longer be safely driven at night. Spare parts are not available and the only fix is to replace the entire headlights at a cost of over $2000. There should be a recall to replace the headlights as this is a safety issue of not being able to see.
Due to the plastic bowels in the headlight projectors, which are chrome like lined, and the high heat of the hid bulbs, this chrome like coating has burned off making the light output of my hid head lights very dim. The outside of the bowels have gone from a chrome like coating to a bronze/caramel color/coating. This problem is very obvious. I have had other vehicles with hid headlights, and the light output of those cars is easily double or more, to the point where alot of times I have to drive with my fog lights on just to light the road up to be able to see well enough so that I don't have a accident. I have pictures I took of the discolored bowels im talking about on my phone that I would be able to send.
My BMW 2003 330i is equipped with zkw headlight assemblies that have plastic xenon projector bowls installed inside the headlight assemblies. After several years of usage these projector bowls burn out and as a result, the reflective coating that allows light to be focused through the projectors are burned off reducing effective light output from the headlight assembly. Upon inspection, both my headlight assemblies suffered approximately 50% loss in effective light output due to burned out xenon projector bowls and I found that my fog lights were putting out more light than both my zkw headlights. This problem affects all 3-series sedans made from 2002 - 2005. There have been many people who have, as a result of BMW inaction to do the right thing and correct this serious safety deficiency, either replaced their original zkw headlight assemblies with depot aftermarket headlight assembles or have replaced the defected zkw projector bowls with al projector bowls or fx-r projector bowls. This problem needs to be addressed as it is a serious road safety issue while driving at night.