I am in the process of building a Car PC (vehicle not originally equipped with SatNav). I would like to connect the PC to the factory AMP, however without disconnecting the OEM radio unit. (ie. AMP is used by Car PC whenever PC is switched on; however AMP is used by radio whenever radio or both PC & radio are switched on)

I was wondering if anyone who has biult his own Car PC managed to connect it to the factory AMP in this way.

Any help would be appricated.