I'm hoping someone can help. I just purchased a used 1991 500SL. When I shut the radio off, and even shut the car off, there's a noise coming from the front right speaker. It's like a "thumping" noise, like a heart beat. When the radio is on you don't hear the sound. It's the weirdest thing!!

Help!!

 

try disconnecting the wire directly from the radio for the front right speaker.

if the sound is gone, then it's from the radio...if still have, then check the wiring for short.

 

Thank you. We did take the radio out and the noise stopped so it's a problem with the radio. I guess my next post will be, what to do with a broken Becker Radio?! Thanks again.

 

you can have it fix. replace a capacitor or condenser.

buy another one.

 

I sent my Becker Grand Prix to Becker North America and had it repaired; cost something around $200. I wanted an original radio; if you don't, just buy a new aftermarket radio.
Incidentally, be certain it's the radio, and not one of the vacuum doors in the climate control system which is bumping as the vacuum leaks off and it moves. sometimes they will bump or groan. there are at least two or three of them behind the glove compartment.