So i am sixteen and recently came into possession of an 850t estate as my first car. Driving it around for the first few weeks i noticed that only the front speakers were coming on (door speakers not dash speakers) didn't bother me to much as i don't drive anyone around so the lack of music in the back seats was eh. However, while driving the other day i took a hard right and the sound switched from all front to all four speakers in the back (rear doors and pillars). I checked to make sure the connections were secure this morning and for about thirty seconds all but the dash speakers were functioning then the front door speakers cut out again. Any advice?

 

there are a few things I'd look for. 1) if you hear scratchiness when changing the controls in the head unit, you may need to clean the "pots" ie open up the radio and spray in electronics "tuner cleaner". Replacement head units are pretty easy to fine on eBay as well. Just make sure if you buy another Volvo unit such as the SC816 (with the in dash CD player) make sure you ask for the right color (ie black or grey) and that the seller provides the 4 digit code. They snap right in and can be had for $50 to $75US, 2) If the sound cuts out completely you should check wiring. Start with the connector at the back of the head unit, cleaning the contacts with your electronics cleaner spray or similar) and make sure the connector snaps on with appropriate pressure to make a good connection. 3) check connections at the speakers - this is a bit of a pain as you'll need to remove door cars or for the dash speakers, you may need to access by popping off the vent ducts and lifting the dash cover (again a pain...). 4) if the sound is just fuzzy, its quite possible the speaker surrounds are torn (that's the rubber ring connecting the paper cone to the metal frame). If that's torn up, you can shop for replacements or just swap in new speakers. Its also possible for a speaker to fail when the spider wire between the coil and terminals break off. if that happens its easiest just to replace the speaker. 5) last thing to look for is the wiring between the body and the doors. The wires go through a protective sleeve so its rarely the fault, but if that's torn up, you may want to wiggle the wires to see if that changes anything.