Randy,
Thanks for your reply. Where is the factory amp located in the car?
Do I need to use the factory amp if my aftermarket radio has amp built in?
Is there a wiring diagram anywhere for the amp wiring? (been searching online)
Are you suggesting the factory amp needs power...maybe from the switched accessory wire?

My C230 didn't have an amp so the wiring to the new radio was quite easy.
Paul

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1999 C230 Kompressor
1998 C280 Son's car
1999 C280 Totaled by other Son