Electrical problem
1997 BMW Z3 6 cyl Two Wheel Drive Automatic 38000 miles
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I noticed that my lights fluctuate. Headlights, console lights, etc. Even with the headlights off my instrument panel lights dim and brighten. It is not a constant fluctuating. Maybe every 20 seconds or so. Car seems to run fine other than that. Can you tell me what the problem may be?
Thank you,
Dennis

I would definitely want to inspect the alternator output for any anomalies such as too much A/C voltage in the output or poor waveform from a failed or failing diode in the . Prepare to insect the grounds and the various connections between the battery and the alternator. It may require replacement of the alternator.

Thank you very much for your response. I'm not good at the electrical part of car engine but you gave me some information that I can use and try to troubleshoot the problem myself before taking the car to the repair shop.
Thanks again,
Dennis