Guys , just a heads up as I've been beating myself on this trying to troubleshoot and searching the forum etc.

If you program the PAC steering wheel control module and everything works EXCEPT volume control, make sure that mini jack is plugged all the way in on the pioneer head unit. If not fully seated, it will suprisingly still control most functions, just not volume.. only took a few hours to figure that out.

SL

I had the same problem for a while to until i said screw it took the head unit out and taped that connector so it would stop moving around. Been good for a week now. Fingers Crossed.