I was driving home one afternoon and the radio in my car flashed on and off about 8 times and then stopped. The radio is an aftermarket Alpine CD player. The next day i was driving and pressed the button to roll the window down and the buzzer light on the dash came on, so i had to press the window button several times before it went off. It did this several times on the way home. Any sugestions on where to begin with these symptoms?
Also, my door locks are not locking and unlocking properly, especially when the car is not on. I assumed this was a vacuum problem, so i checked the lines under the hood and everything seemed intact. Is there anywhere else to check?

Sounds like a weakening battery or a loose ground on the battery.Start there

What year 300d?

If you lift up the carpets, you will find a plethera of vacuum lines for the door locks. There are T-sections where you can plug in a hand-held vacuum tester to isolate the leak. Cheers, Andrew Seidel.

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86 560SEC
85 500SEC Lorinser
83 300D Turbo
75 240D