I apologize in advance for thread length.
I appreciate all the suggestions so far. I am leaning toward an inexpensive (~$40) "experiment" with the Electical Connection bluetooth (BT) aux input. It should allow the Zumo to work with the aux button selection into the bike's audio. It will eliminate ground loops. If I later decide to go to BT headsets, this should make that easier as well. I can pair my bluetooth cellphone either to the bike or the Zumo. This would allow use of music stored on/through the Zumo or the cellphone, but not sure how the gps alerts work with music playing (similar to the bike's intercom mute?)
I don't think I would be able to use wired headset mic input to interface with the cell phone this way, but would be pleasantly surprised if it worked. A BT headset should work though. (I understand the safety concern with talking on the phone while driving, and don't use a phone while moving.) The 3.5 mm aux input pin to the bike would be in use by the BT input device, and only the power leads on the Zumo cradle would be needed. Using the mini USB Zumo input for power instead of the cradle power (if the mini USB can provide enough current to charge or run the GPS) might be an option if not blocked by the cradle, but it would not be weather resistant. It should work, if the same mini USB powers the GPS in a car mount. The passenger would be able to hear the gps audio on the bike. Not sure of any limitations on number of paired BT connections this way. This solution would require the bike's audio selection using the Aux button.
Has anyone compared the various BT connection devices from Electrical Connection, Edsets, J&M, Sierra Electronics, Siena, etc? Any pairing limitations found?
The Sierra Electronics solution is the next step for ~$60 to add intercom input using the bike's automatic mute function. That would not use the aux input for music, but enable gps alerts through the intercom. I could use the normal selectable Aux/FM/XM for audio source. If using FM or XM, any music playing simultaneously on the gps would likely automatically mute the normal bike audio, so I would have to ensure the gps music was not left playing when switching audio input buttons. I am thinking this still would not enable mic input to the paired cell phone. It seems that making that leap requires a massive price jump and would require removal of the two added modifications so far (unless a fast switching mic splitter would work).
I used a much more expensive Kennedy Cellset (not sure if they are still in business - if so their website says you can't order online; you have to send an email) on my 2002 GL1800 and a Zumo 550. That had alternator noise that needed an additional ground loop isolator. I think I remember using an isolator from Sierra Electronics that worked well, even after they told me it wouldn't. I think the cellset II-C-0 option from Kennedy would still work, but was unsure which interface to go with. (The whole part selection ordering process involves a two page flowchart and numerous tables which adds to confusion.) They list two gps interfaces for a Garmin gps. The Zumo 595LM was not specifically listed as an option (making me wonder if they are still in business or just haven't updated their literature/website). For those using cellset on the 595LM, which did you select?
From the feedback, it appears the J&M solution connects everything, but may delay switching to gps alerts too much, resulting in cutting off the leading portion of the alert. They have a nice installation video though.
I am hoping that using BT will result in reducing cost down to ~$100 versus $250-$350, plus eliminate unwanted audio noise from alternator or other ground loop sources, and allowing future BT expansion. The massive Zumo cabling cluster can be cut down to just power to the $70 cradle through a 12V cigarette lighter type socket or USB socket with more reasonable length. I am not interested in paying significantly more for similar results, so this isn't a cheap out solution after paying big bucks for a premier touring machine. I understand the mic signal is very small and needs to be amplified, resulting in any induced noise also being amplified (such as the alternator whine issue - making cable routing paths important).
I would hesitate to cut into mic audio cables that might impact whatever EMF shielding is already in use on the cable. Looking at the J&M integrated solution, cable routing all the way back to the rear under the seat could expose the mic audio to the EMF produced by the the alternator if mic audio is in the cables going that far back. Most other options limit this exposure, staying in the front left pocket area except for power to the battery/fuse box for direct/switched power.
Has anyone else done a similar "experiment"? So far I have ordered the Zumo and EC BT Aux input. Wish I would have kept the old Cellset, but was unsure how to reconnect everything to stock configuration after 15 years and no directions retained. It was time to start fresh anyway with the 2017 GL1800.
