2003 passat radio connector

There is none! The antenna power is sent down the antenna wire. So basically if you don't use an antenna from a older VW that has the external amp wire then your reception especially on AM will suck.

I installed an aftermarket stereo in a 2002 non-Monsoon Golf. I don't believe there is an antenna connector wire in the harness. Instead, my new stereo has a blue antenna power lead coming out of it.

I had to buy a special VW antenna adapter from Crutchfield. This adapter connects the existing (round, thick, black) antenna wiring up to the new stereo's antenna input, but the adapter also has an auxiliary connector for the blue antenna power lead. Here's a link to that adapter: