Well when i was programming my swi-jack(adapter to use steering wheel controls on aftermarket HU) my vol down wouldnt program but all the other buttons worked. so i took it appart and tried using one of the other push buttons on the rubber pad inside the controls and that didnt work. I also tried programming vol down to another button and that worked. is there anyway i can check to see if one of the diodes or resistors or somthing crapped out. Or anyway possible to check it or am i just better off buying another one from a junk yard?