I had the rear AUX port installed on my HK head unit when I sent it to Iron Cross to have preamp outputs installed. It is a handy solution when leaving a device plugged into the head unit all the time. The only thing I don't like about it is it keeps AUX as a selection on the display all the time even when it is not in use. I didn't have an issue with this at first but when I added a bluetooth module and the iPod module that totalled seven selections, so now I have to flip over to a second page to get to the iPod selection. It's not a big deal, but it is annoying at times.

I will say though that now since I have bluetooth and iPod control added to the stock HK unit I am happy with it. I can still play CDs, use my CB and intercom, connect my phone through bluetooth and skip tracks forward and back, and access all of my music on my iPod. The one thing I don't like about the setup though is the FM tuner isn't as sensitive as I'd like. Realistically though I don't know how well an FM radio can pick up on a bike, there's not much of a ground plane to reflect a signal off of.

 

OP, not sure if this is pertinent to your question but I bought one of these just out of curiosity to see if it would play jump stick music even though I have a new bike. I did plug it into a couple of the 3.5 jacks on the dealer's used inventory on the pre-14 bikes but I was never able to get it to play my jump stick music but I also have zero electronics knowledge.

https://www.ebay.com/itm/3-5mm-Male-...53.m2749.l2649

 

True, but isn't FM, AM, WB, etc in the display when not in use also?

 

Yes, but since it puts the iPod selection on the second screen now it takes seven or eight presses of the right thumb button to select it. If it was on the first screen I could press the left thumb button once to bring the menu up then press the button on the radio to select the iPod. A minor annoyance, but if I had it to do over again I would not have had the rear AUX jack installed. I never have used it now that I have the other input options.