996-Fan

Hi, I am in the process of upgrading to PCCM+. The prior owner installed a bluetooth solution that uses an FM modulator (TranzitBLU HF ISFM2351) (https://isimple.com/products/install...your-car-radio). In the process of removing this module, I found where they tied into the power and ground. What's perplexing is that they tied into a wiring harness that is not connected to anything.

Is it normal to have this harness that's not connected to anything? Perhaps it's for a system or options my car does not have?

I need to disconnect these wires and have zero experience with wiring. Any tips would be appreciated.


Bluetooth module is tied into this harness that is not connected to anything.

168Sierra

IIRC that unused connector was for the optional phone package. It is a good place to tap for + and - for an accessory

996-Fan

That is very helpful - thank you!

996-Fan

I worked on this installation some more and and faced the dreaded "No Sound" problem. The radio and CarPlay appear to work, just without any sound. This is a 2003 C4S with BOSE & MOST.

Things I have tried:
- disconnecting the battery several times and switching from CAN to AMP
- put MOST bridge on CD changer as per instructions (even though the other end of that cable does not attach to PCCM so I am not sure why that is needed)
- put MOST bridge on the cable inside the dash while the other end was disconnected from the CD changer
- disconnected and reconnected the microphone plug
- disconnected and reconnected the old stereo harness (does not "click" into the PCCM+ - I tried that several times. It's in there but not enough to click)

What I did not try was to unplug the plastic cap on the MOST adaptor and actually plugging in the cable that goes to the CD changer. That fixed it!