Three problems related to wiring have been reported for the 2003 BMW 325. The most recently reported issues are listed below.
Ground wire on rear light wiring harness has burnt through damaging plug and socket. Potential for fire.
BMW 325i rear blinkers shorted out causing electrical wires to burn. While driving my BMW a warning light on my console turned on indicating the left rear brake/blinker light(s) went out while at the same time I smelled wiring burning. I stopped the car and all my lights seemed ok, so I presumed it was a faulty sensor. A short while later while driving down the freeway I pulled into the left lane and really pissed the driver off behind me and nearly caused an accident. At this moment I noticed my left blinker was making a fast noise as though the left blinker bulb(s) was out. I pulled over a second time to check my blinkers, fearing I would cause an accident, and all my flashers, brake lights and blinkers were working fine. The warning lights on the console went on and off intermittently. I purchased a new bulb hoping this would solve the problem, but everything seemed ok and functional. When I returned from my trip, I was told by two european auto shops and the service manager of a BMW dealership that BMW is aware of a ground problem with the rear light cluster. When I unsnapped the plastic connection from the rear light cluster, the metal prongs and plastic were melted away. The heat apparently was so hot, the solid metal prongs 1/4" long completely melted including the plastic casing. A BMW dealership employee told me that this issue is common when driving in the city when one is using the brakes and blinkers incessantly, particularly in heavy traffic. "the grounding wire isn't heavy enough to withstand the demand for electricity required by the brake and blinker lights simultaneously". This is a known BMW defect and this can easily cause an accident, as in my case, not to mention a lot of drivers really pissed off when I cut in front of them thinking my blinkers are working. This is an issue BMW should repair!.
The contact owns a 2003 BMW 325i. The contact stated that the wiring harness for both tail lights have shortened out and melted. She is concerned that this failure could cause her vehicle to catch fire. The dealer stated that this is a common failure among the 2001-2003 models. The current and failure mileages were 57,200.