Another dumb question...
 

I have a 2012 heritage, with the 103 engine. It has v&h slip-ons. Dunno if has the cat still. I have that annoying decel pop, and need to have that gone, because it annoys the help out of me. Sounds like something a kid with an evo sporty with exhaust leaks would ride. Apparently, I need some sort of aftermarket pcm of ecm or whatever it is, to tune that out. Before I buy one of those, I want to make sure i don't already have one. Where would i look? Under the seat? Somewhere else? I know there are some electronic black magic boxes under there, but I dont know if everything is stock or not. Dont beat on me to hard, I come from shovels and ironheads...i can tune those. But this stuff...it's very much a different world...

Look under the seat, not familiar with your bike but if you have side panels look under there. Problem is, if it was tuned with a flash tuner it doesn't have to be on the bike anymore. The dealer can tell if it has a stock tune or not. Sure sounds like you need a tuner though with the popping but check for exhaust leaks first. Just my opinion but there's nothing like a good dyno tune if a competent tuner is available in your area. You can get a power vision from fuel moto and those guys are usually pretty close. Don't try to save money when it comes time for the tune.

I take it you bought the bike used?

On my 17 Deluxe i put my FP3:
https://cimg0.ibsrv.net/gimg/www.hdf...a8ed001ec9.jpg
https://cimg3.ibsrv.net/gimg/www.hdf...b43500a030.jpg
If you have one of these you need to down load the app to run it.
It allows you to set/control the pop.

If the previous owner did not leave it under the seat your SOL though (as they do not have to stay plugged in).
There are other brands out there, but that is the general plug location on the newer 103's

The cat's where in the stock mufflers so they are gone with the slip ons, HD dealer can tell you if it has a flash. I use a V&H fp3 on my 16 Deluxe with great results on popping and over all rideability, I believe your bike has a 4 pin canbus system, V&H makes a FP3 for your bike per their website, Fuel moto is another way to go, both have very good customer service. Good luck, ride safe

Thanks for the info. I'll pull the seat and see what I can find, and go from there.