I inherited a 2013 Elantra- has sat. radio but no bluetooth- is the steering wheel already pre wired on that left side so if I could
purchase the buttons from somewhere and install would that work? Or do I have to add on to radio a bluetooth whatever?
The wiring is probably there but you'll most likely have to buy a new radio to get the feature and at least a button assembly for the steering wheel. Depending on how complex the software is you may also have the computers' firmware/software updated so it knows to allow the feature to operate.