2003 MOST cable routing?

Can someone describe to me how the MOST cable is routed? In particular if it had been equipped with a CD changer or phone system, that had since been removed. Here's what I have....a MOST cable terminating at the head unit, and a MOST cable terminating at the amp. I understand this is a looped system. I'm just trying to sort if I have a break in the loop. How do other components tie into this system? is there a junction box? or does the cable go from the HU to the CD changer, then out to the amp?

Find the Dension install instructions. I bought mine from Bumper Plugs, a site sponsor. They also have a graphic that I can't copy to this message. "You will receive your Dension soon and I hope you (and your installer, if using one) will review the notes we sent. We are happy to take your emails regarding installations, but we have put a lot of time and energy into the files we sent you, and the threads are a good overview for installation too. We have also attached a graphic showing how the basic layout should be (depending on your system, this may or may not apply) along with an image showing the optical connections and identifying each of the referenced optical ports for you. The basics are this: The Porsche optical system goes from head unit to amp. If you have nav and/or cd changer, it goes from head unit to those, then from those to amp. The Dension fits in the optic loop b/w the head unit and amp. If you have a cd changer, the Dension and cdc CANNOT reside on the primary loop simultaneously. This is a critical point that many installers miss. See notes below. If you are installing inside the cabin (no cdc), you remove the inbound optic cable at the back of the radio, and use the connectors to form a connection to the Dension, using the second hole on the left side of the Dension in the first optical port. There are FOUR holes - #1 and #2 make up the primary optical port, #3 and #4 make up the cdc optical port. Take the cable that was in the radio (inbound), and plug it into hole #2 using the gray connector. Take the Dension optical cable from the kit, and connect from radio (where original was in connector) to hole #1 using the same gray or black connector you used above. That's it for this type installation. You now have light going into the Dension through hole #2, and out from the Dension from hole #1 and back into the head unit. You then pick up unswitched (constant) power from the dash area (lighter, fuse panel, etc) and tap the power connector for the Dension. You can zip tie the Dension to the strapping on the firewall above the passenger footwell area, or velcro it to the carpet behind the head unit/stack too. Route the iPod and Aux cables to the glove box (loosening the glove box makes this easier). You must connect the Aux cable and have the Aux switch active. Place it in the glove box for best use. You can route the iPod cable to the lower storage area if you prefer, and if you are installing inside the cabin. If you are installing with cdc in the front trunk, the Dension can reside beside the cdc. The cable going TO the cdc from your radio should now go to hole #2. The cable in the kit can go from hole #1 to the amp. The cdc plugs into holes #3 and #4 as described above, so that the cdc becomes and accessory on the Dension menu. Many folks run the cables through the firewall at the larger rubber grommet behind the battery compartment. Cut a slit in that grommet and feed a fish wire in from the trunk to the cabin (passenger footwell area). Then feed the smaller ends of the iPod and Aux cables (and mic if using BTA) back through. Connect to the Dension. Pick up power from the cd changer power harness. MAKE SURE TO SET YOUR DIP SWITCHES ACCORDING TO YOUR SPECIFIC MODEL AND HEAD UNIT. "Gee, I can only see track numbers on my CDR or PCM radio, this thing is broken" Nope. CDR is not text capable, as described earlier. It will allow you to move track to track using the head unit controls, but the CDR cannot display track names/artists, etc. You can program the system to control it by ipod if you prefer. Refer to the Tech Guide that was emailed. On PCM, if you see numbers, you need to go to the Tech Guide as well, and read up on how to program/set the menu. CD6 is your friend. Menu -> Source -> iPodGW (gateway), then HOLD DOWN the FF button about 8 seconds to lock in. This puts the PCM system in control so you will now see full data. Note the chart in the Tech Guide – print that page and carry with you for a while until you get the hang of all the commands. "Callers can't hear me, what's wrong with the mic?" Some features and sensitivities for the bluetooth system are phone dependent. For the mic issues, the BTA is now programmable. Using the # and * keys of your PCM, you can now adjust the volume and the sensitivity. *** (then any number from 1-31) for the mic sensitivity. ### (then any number from 1-31) for the volume settings for the speaker. We have found the sweet spot can vary depending on the vehicle, the mic location and the phone, but 8-13 is a good range to try. Using the PCM keys, not your phone, dial ###8 (for example) and SEND. Try the same for the *** settings and see how it goes. "My installer is a real pro, and he did everything right, but my system is giving me errors on the screen" This means that the optical loop is likely open somewhere, and as good as the installer was, they may have missed something. Again – optical goes head unit to dension, dension to amp. If nav is in there, that's fine. If cdc is in there, that's wrong – it must be on the second optical port of the Dension (holes 3, 4). Also check to be sure the amp connection is good. The Aux switch should be on the white circle for iPod function (and radio, etc). IF YOUR VEHICLE DOES NOT HAVE A FACTORY CD CHANGER, A DEALER MUST PROGRAM THE VEHICLE FOR A CD CHANGER, even if your Dension starts working – it must be programmed. Your unit will stop working, it won't provide all the features, and you will become frustrated. Make 100% sure the dealer activates the cd changer in 'both columns' on the Porsche Tester menu when they program. Don't neglect this, even if your unit starts working. NEVER have the factory telephone activated – the BTA unit, if included, works through the Dension, not the vehicle system and both the BTA and factory phone cannot exist at the same time, so do NOT have the telephone activated, only the CD Changer. That should do it. Email works best for us as we can respond day or night. We're here to help along the way, but we do ask that you please read the material and provide it to your installer."

Quotes source post: 12999291

Ahhh! OK, that alone is a huge help. Thanks!