Thanks for the replies.

Does the buzzing happen with the engine off or on?
I believe its with the engine off.

Does it increase with RPM's (if the engine is running)?
Don't know

I'll pass the advice on as I'm going back in later today.

Pardon the ignorance, but could you explain the effect of bypassing the amp? I am assuming I will get more power, and better sound with the amp. While not an audiophile, I certainly would like to know I'm getting my bang for my buck with the unit.

thanks

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1993 300E
1999 E320 Estate