Thanks for responding. To answer your questions first:
1) I think it has the "old style 30 pin connector". It's an iPod Touch Version 6.1.6 (10B500) with the wide, flat iPod plug. I checked the Amazon link you supplied above and the iPod connector is much narrower than on the cables I have.
That sounds like a 30 pin connector. That would be consistent with an iPod Touch running iOS 6.1.6, which is about a 5 year old version of iOS and was long before the Lightning connector was introduced. To be sure, this is what a 30 pin connector slot looks like (see the wide slot on the black iPod Touch in the image...kind of hard to see...the 30 pin connector will be about an inch wide):
And this is what the 30 pin connector on a charging/sync cable will look like:
OTOH, this is what a Lightning connector on a charge/sync cable looks like (it is about 1/4 of an inch wide):
2) The stereo does not have its own USB port. That would have been too easy. That's why I had my mechanic hard wire a box with 2 USB ports into the dash of my '94 Lebaron convertible. Without the cable I'm looking for, I can charge it while listening via the earphone jack but the quality of sound is noticeably deficient. Whether the car stereo receives the signal from the main jack or the earphone jack makes quite a difference.
This additional information tells me that you do not need a car charger plug for the cigarette light socket and the power charging end of the cable can end in a USB port. So, assuming it is a 30 pin connector, then the item that I linked to in the second link in post #4 above should nominally be what you are looking for and might be similar to what you currently have. Go back up to post #4 (this link will take you there) and check out the second link in that post.
Ironically, the car stereo comes with an iPod clip that does the same thing as the cable I'm looking for, and when using the clip, the iPod fits in a drawer behind the removable faceplate of the stereo so no one even knows it's there. That's why I bought that stereo in the first place. The problem is that when using the clip and having the iPod and stereo on 'Shuffle", it will work perfectly for a while and then, for no reason, latch onto a song from 'Shuffle' mode, change the mode on the stereo from 'Shuffle' to 'Album', and endlessly play all cuts from that album that happen to also be in the iPod.
It likes "American Beauty" so much that I had to remove all cuts from that album because it would happen almost every time a song from it came on. That's why I don't use the clip. I can't be pulling over every 20 minutes to correct the problem.
Built-in iPod/iPhone support does seem to have quirks at times with third party car stereos.
I have my share of quirks when using my iPhone with my Alpine. For whatever reason, it regularly forgets what the iPhone was last playing when I reconnect it and will resort to playing the first song alphabetically in my library (ABC by the Jackson 5...don't judge ). This is even though the Music app "knows" the last song that I played and theoretically it should pick up right where it last stopped...and sometimes it does. I believe the issue is that when I connect the iPhone to the head unit, it is the head unit that controls what is being played (through the Music app). Sometimes it then remembers where it was (typically if the car has only been sitting there unused for short period of time...i.e. when I run into a store, etc) while other times it does not (typically after the car has not been used for long periods of time). But, it is not always consistent.
The other quirk is that sometimes when I advance a song or go back a song, it will leave the playlist that I am playing. I believe this is again tied into how I starting playing the playlist...i.e. whether I started it through the car stereo interface or directly on the iPhone.
So, I too encounter quirks with built-in iPod/iPhone support with my radio. I am not sure if quirk is the radio or the iPhone. This can be an argument to do what you are doing by using the aux input (my radio has one as well), but then in my case, I can control the iPhone with my steering wheel controls (i.e. forward or back a song at least).
I hope the background info helps. I didn't include it originally because I was skeptical that it would be considered long winded, useless detail.
Personally, I never consider anything long winded, but then I tend to be long winded myself. In all seriousness, when asking people for help on a forum, it is generally better to give more details than less (this is kind of also suggested in the BC Welcome Guide under item #5 in the form of "...please be as detailed as possible..."). As I alluded to in some of my previous posts in this thread, someone helping you will only know what you tell them. And many times what might seem obvious to you is only obvious to you because you are sitting there in front of the computer or device, while we are not. For example, in this case, without knowing what kind of connector your iPod Touch has, there was no way I could really find you that cable or something similar without making some assumptions and/or spending more time exploring both options. And beyond that, I then did not know if you need the car cigarette adapter or not (or if just a USB plug would be enough) until you mentioned that you did have USB power ports installed. Nor did I know if you were using headphones (which then the headphone jack likely would have been enough) or plugging into an auxiliary port of a car stereo...I actually assumed (and made a you know what of me) the former based upon your phrasing in the original post, thus the suggestion to just use the headphone jack that you did not appreciate.