pauliehcfr

I have a 2004 545 with a manual transmission. Only when the weather gets cold...40 degrees and below, do I get this problem....When I upshift or downshift sometimes, the radio sound will cut out momentarily, the interior lights, if on, will flicker, the heat and air will cut out momentarily, and I'll get a dynamic drive malfunction. All the symptoms won't occur altogether, but mainly the radio and lights will be the issue. I replaced the alternator and battery and had it registered last year because of this and it was fine all summer until it got cold again, so I'm thinking it wasn't the alternator. Anyone have a similar experience that was fixed?

lincvert

My radio drops momentarily while upshifting occasionally as well. I hadn't pinpointed it to <40 degrees, but I will start to pay closer attention. I did notice that it only happens with shifts over 3k RPM before the engine is fully warmed up.

I have another thread with some other electronic things I can't explain. https://5series.net/forums/topic/106...5#entry1265035 The good news is that the car runs perfectly right now. I just wish I knew what the issue was so I could fix it. It doesn't seem like many people have solved these issues, or they just don't post them. I guess it is easier to sell the car when it is running well.

Good luck.

Masterspy

Do you still have the original battery, chances are you are due for a new one.

BMW_Guy

I have an '04 545i also. About a year ago, I got water in my trunk which shorted out the electronic controller under the spare. Every time I braked hard, the idrive display would black out, radio would cut out, fan would stop, wipers would wipe, etc. You might not have water in the bottom of the spare well, but the symptoms are very similar which makes me suspicious of that module. Anyway, it's something to consider.