This car has about 100k miles and most of the systems seem capable of working properly, however, systems work and then either don't work at all or don't work properly. Examples: Dash turn signal indicators/speedo/tach light work and then don't work. Memory seats either work or work improperly. Sunroof works, doesn't work, and then works improperly. Climate control dash unit, stereo, wipers either work or don't work. Sometimes dash light will work fine and then not turn off even with the key out. All fuses are good. Pulling some of them to reset seems to get some things working properly again but not for all problems and not consistently. It seems like it could be partial power supply connection problems to these systems but I am unfamiliar. Any idea where to physically start looking for this ghost in my machine?
Intermittent Electrical Problems/Failures on 2003 BMW 325xi
by Colorado Monty in Idaho Springs, CO on April 27, 2011
ANSWER by Superbob on April 27, 2011
It sounds like switch problems. If the car has been exposed to dust or moisture that could have gotten into the switches, this is possible. That's where I would start looking, use a meter or a testlight for diagnosing the switches. If the switches are working OK, then the problem is deeper and you may need a Beemer expert to diagnose it. If you want to find a BMW specialist, here's a directory link for you: https://repairpal.com/directory?address=80452&car_brand_names=BMW
ANSWER by ZeeTech on April 27, 2011
Make sure that the battery connections are good, not loose at all. You can check the ground connections also, the ground cables are brown and more of them can share a connection. The problem could be also with relays, like an accessory relay, which is feeding the failing components. If you are not familiar this car I strongly suggest to find a good BMW specialist in your area. Zee