Hey guys, I am looking to replace the stereo system in my '80 300CD. I have read some threads that say one should modify factory wiring to remove a "fader". If someone could clarify this for me please. Also, what size speakers can I put in the factory locations? Thanks guys

The problem is your OE radio is 2-channel and all new radios are 4-channel.

The OE fader can (surprise) only handle two channels, and in any event new 4-channel radios come with a built-in fader.

You need to cut the rear speaker wires off the OE fader and extend them to connect to the back outputs of your new radio.

Just disconnect the front speakers from the fader and connect to front outputs of new radio.

Some folks get lazy and just run two channels to the OE fader, but this loses them half the power of their new radio.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles