[01BluBenz]

I recently acquired an 84 380sl and I’m trying to get sound out of the radio. There is some sound but very low. Volume won’t increase. I replaced the speakers with new wiring and hooked them up to radio and I got low sound. It’s an aftermarket radio so I am using knowledge I have about those brands of radios.
Does the radio require an amp to make sound or no? Could there be a bad ground and where are the grounds ? I found one in back of radio , but I don’t know if there are more. Any help is appreciated. Tha

 

[Skylaw]

Does your head unit have speaker level outputs, or does it have preamp outputs? Some radios will have both sets of them. Check your head unit for two sets, and if there are, switch to the other set. If you have only one set, the outputs are likely preamp level, and you need a separate amplifier.

Bad ground ususally results in no output (if it is in the power circuit) or alternatively a hum or spark plug noise if bad ground to the chassis.

 

[01BluBenz]

I have speaker level outputs. Sitting in car with switch on the radio is audible. But, I try to increase volume and it doesn’t increase. Sometimes it decreases. I can turn counter clockwise and volume level numbers increase but volume doesn’t. I can turn clockwise and volume level numbers decrease but volume doesn’t change. I think the best thing would be to get a new stereo and start over. That way I know what I have.

 

[Skylaw]

You are probably correct, and while you're at it you may find a more modern HU with an "older" look that will still give you Bluetooth capability for your phone. The R/C107 forum has some good information on such. If you prefer to keep the original, check the Component Level Repair thread in the stickies of this forum. They may be able to fix your radio.