This is my first BMW; I bought an e90 2006 325i sedan with the low/high beams not working on the passenger side. I thought it would be a simple fix, as simple as replacing the bulb, but it is turning out to be a nightmare.
I have gone about fixing the problem by trial and error as the dealership recommended. I started by switching the OEM bulbs, and found that the D1S bulb with attached ballast was not the problem as it lit on the driver side.
I went ahead and replaced with two D1S 6000K Phillips bulbs at the time since I was going to do the upgrade anyways, and obviously, the passenger side did not light up. I replaced the 40amp fuses for the headlights and nothing happened. I took the car to my mechanic to have the ballast control module inspected and it turns out that switching the driver side control module fixed the problem. Therefore, I sent the passenger side control module to a reputable electronic shop to have it fixed and they could not find anything faulty with the unit. I proceeded to order another control module and my mechanic installed it and it fixed the problem. He showed me that both the low and high beams were working on the passenger side now and the headlamp error message on the display disappeared.
I got home and admired how the bulbs looked again, and decided to go through the different light control modules in the car (automatic, off, parking, and manual). Sometime between switching from automatic mode to the other 3 modes and testing the high beams, I noticed that the angel eyes on both sides flickered twice and the passenger side low beams turned off again, and the error headlamp display
I was so disappointed as I had been trying to fix this for the past month waiting for parts and reading forums on similar issues.
I am at the point where I will replace the bulb and ballast again, thankfully I kept the OEM bulbs and ballast, to hopefully find out that only the bulb burned out somehow.
I phoned the dealership and explained to them what had happened and they recommended having all connections rechecked to make sure nothing was lose. The only thing that was not replaced was the wiring harness connecting the ballast to the control module. Apparently, this harness is not sold independently and the parts department quoted me $5600 for the wiring harness for the whole car, which they recommend so that there was no splicing with the wiring.
I have also read some FRM module discussions and some computer reprogramming ones that have helped others in similar situations, but I am unfamiliar with the FRM module and skeptical about computer reprogramming since the error message disappeared with the new control module installed.
I know that headlamp malfunctions are a common topic in these forums, but I have done my research and have not found similar cases where a control module fixed the problem and the assembly stopped working within minutes after testing the lights. I would truly appreciate any input or guidance.