Ok so the car is a 2002 9-5 aero hot I'm not sure but I assume it has the as3 system. the problem is an intermittent drop is sound as if one of the speakers is cutting out, so first thought is loose wire but to be honest I wouldn't know where to start.

should I pull out the head unit or start by checking all the speakers, not even sure how to check the dash speakers??

Any advice greatly appreciated

thanks folks.