Sat Nav retrofit

Hi,

I’ve been able to retrofit lots of parts into my zetec s including heated seats and converting the headlights from the halogen h15 drl to the led drl strip. My next project has been to install satnav, I purchased all of the necessary parts and the satnav works great, the only issue that I’m having is the satnav audio, when a route is set music will lower when an instruction would be given however nothing is said. I’ve checked the loom for the FCDIM and radio but can’t notice any difference between my cars loom and the donor cars loom. I’ve read that I need to connect two audio wires from FCDIM pin 6 to radio pin 4 and FCDIM pin 12 to radio pin 5, I am unsure how to do this as wires going into the FCDIM pins are hard to access. Has anybody done this and can explain how to fit these two wires for the satnav audio. Below are photos of the FCDIM loom, thanks