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Hi all, my radio recently stopped functioning over the winter (turns on, can search stations but no sound) and the retractable antenna started doing some unusual things. It would retract and extend randomly, whether or not the radio was on or off. It has now settled in the extended position whether the car is running or not. I went out of town for work on short notice for 2 months and forgot to disconnect the battery, when I got home it was dead. No big deal right, I jumped the car and it fired up right away. But after taking it for a 30 minute drive it would not crank, 11.5V at the battery when the car is off. I'm wondering if the two are related or if anyone else has had this issue. The battery is 2 years old.

Also, I read that 1999-2002 E class or SLK radios will plug and play into the 400E, is this correct? I've found this one on ebay for a reasonable price. TIA

 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,745 Posts
Before addressing anything in the audio department, I'd get a good, 24 hr charge on the battery before trying to start the car. These cars want and need full voltage all the time.

Report back

Sent from my XT1710-02 using Tapatalk
 

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Premium Member
2014 G550, 2000 SL500, 1995 E320 Cabriolet, 1980 TR8
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1,230 Posts
Yes, the W124, like most modern cars, has a key-off current drain for things like radio memory, the convenience module, and the alarm system, so it does not surprise me that the battery could go dead after 2 months in storage, especially if the battery was older to begin with (the A-Hr capacity drops as they age). I have seen a bad MB radio draw excessive current for the memory backup, but I believe this is rare.

11.5 volts is low, indicating a lack of charge or that the battery may be "sulfated" which is common on non-deep cycle batteries after a complete and lengthy discharge. As Jayare said, you need to give the battery a good 24 hr charge. I prefer to use a good old fashioned manual charger because I have found that many of the new "smart" chargers are not so smart and will give up on a battery that could otherwise be charged. If the voltage does not return to around 12.6 volts and/or you have starting issues, the battery is bad and needs to be replaced.

You also need to check the charging system voltage which should be between 13.6 and 14.6 volts with the engine running to make sure the battery is being charged in use.

Lastly, the Audio 10 from the 1999-2002 E class or SLK is plug and play for the later W124s, '94/'95. I have one in my Cabriolet. I even hooked up the DB2 optical bus so I could use a CD changer/ipod adapter. I'm not sure about the earlier W124s, but I don't think so.
 

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Discussion Starter #5
Extremely helpful guys, found my old as dirt Mastercrap charger to be non-functional so will pick up a new one and report back. Many thanks
 
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