The radio in my 1995 C36 is driving me nuts! With the ignition in 'ON' but motor not running it works fine, but with motor running, no sound output from the power amp although head unit is on. Sometimes turning the headlights on (in bright) will cause the bloody thing to work. Had Anybody here experienced something like this? Could this be related to my failing engine harness? Radio is BOSE premium.

Regards,

BC36

It sounds to me like you have an alternator problem and this could be due to your failing harness.The alternator is putting out too high of voltage and this is causing the amp or the radio to not work properly. When you are turning on your high beams this is offsetting the over voltage causing your radio to work again. I would be concerned with driving the car and maybe park it till it gets fixed.

Scott@lajollaaudio

__________________
The Mercedes Specialists Since 1986

Scott, you might be right with that. The radios have a over and under voltage protection and will cut out below 9.5 or over 15 Volts.

Scott, I took voltage readings off the alternator as you suggested but they were in the normal range, 13.6 to 13.81 VDC, and pretty stable even when revved. Ant other ideas gentlemen? Am really frustrated.

Did this model come with the speed-sensitive volume control?

Yes, it should have speed sens vol. When you are taking your measurments does the audio cut out or is still only intermittent. If it doesn't cut out I am going to bet it is still over charging intermittently.

Scott@lajollaaudio

__________________
The Mercedes Specialists Since 1986

Scott, I tested it again upon reading your reply. The amp was not working when I took the voltage readings although the head unit was powered on. I turned the motor off and turned it back to the 'ON' position and the radio came on. I took voltage reading with the engine not running (off the battery) and read 12.67 VDC. I started the engine and radio cut off again. Voltage with engine running was 13.80 VDC stable.

Are there multiple +B supply for the power amp? Do you have a pinout of the power amp connector?

Thank you and kind regards,

I dont have pin out in front of me but you should find a large red wire in the harness for 12v. Also it wouldn't hurt to pull the head unit out and do a quick check there on the constant line.

Scott

__________________
The Mercedes Specialists Since 1986

Thanks Scott, I will check for that tonight.

Regards,