Yes as there is a circuit that grounds to allow only a 2 ch output of the radio when there is a fader switch and this is on the cd changer cable. If a wrie is shorted on the cable the cd changer would still work but it could keep the radio from having a 4 ch output. Whille the radio is out you can also hook up a test speaker to the rear outputs of the radio to test for sound there.

Scott

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The Mercedes Specialists Since 1986