I live in Los Angeles and just purchased a 2005 S80 (only 10K miles for a great price of $25,900). Well, the AM Radio reception was awful. So when I got it home, I called two of the nearest dealer service centers. They both said the fix is easy: they install a small metal plate/strip in the pillar by the rear window. Well, now my AM Radio is working like a champ! Here's the info on it: I believe that it was a secret recall item a couple of years back. There is a service bulletin (tech note 39-35) out for this problem. Dealer fix was free and simple. Reception improved 1000%. repair order said "99042-2 antenna amplifier 1 side modifying according to TJ" the part was 30657370. evidently this is a known issue by Volvo and they have this "fix" for it.

I fixed mine last night - I had the same problem with my AM radio signal, except I could barely get any signal at all. I found the problem to be with a loose connection of coaxial radio antenna at the the signal amplifier. The fix was simple, took only a few minutes, but requires access to the signal amplifier - which Volvo secretly hid in the A-pillar behind the driver's side rear door.

The problem I found was the coaxial cable came loose from the signal amplifier - it just wasn't fully inserted onto the connection anymore. The retention clip at the end of the cable is poorly designed and sometimes doesn't snap into place over a circumferential lip on the connection at the amplifer. The amplifier is located under the inside trim panel on the "A pillar" right behind the triangular window between the rear window and the driver's side rear door.

To access it, pull loose about 1-1/2 foot of rubber door seal molding at the rear driver's side door. You'll need to detach the small stainless clip from the triagular interior trim that saddles the metal edge and holds it in place. Push the top of the trim toward the center of the car - it's snapped into place by a snap-in type pin in a socket. Once loose, pull the whole trim piece toward the front of the car. Behind this trim is a small box with some wires attached - this is the signal amplifier.

The coax connection is toward the front and has a plastic retention clip on the end. I found on my car the retention clip was not snapped into place over circumferential groove of the amplifier connection port. Re-insert and press the retention tabs over the grove and I'll bet you have AM reception again. (You may choose to take a rubber band or small wire to tether the cable to the amplifier like I did - since the retention clip was not a very snug retainer device - and you'll never have to do this again.)

I'f you're still not getting good signal, check the other connections on the amplifier, and the connection to the rear window defroster, too.

As a bit of information, the car's rear window defroster element doubles as it's AM radio antenna, believe it or not. This is one of the few places to put a large antenna without having the mechanical reliablility and breakage problems of a power mast-type antenna, yet still avoid signal interference from the rest of the car's electronics and engine ignition/charging system. Since the rear window defroster is large in dimention, by doubling as an antenna, it's capable of picking up a weak signal fairly well and for AM reception that's important. The antenna (rear window defroster) connects to the signal amplifer, which amplifies the signal before feeding the signal via a coaxial cable to the radio in the dash.

FM reception is a stronger signal, plus the coax cable all by its self is a probably a suitable enough antenna for FM. So, a loose coaxial cable connection might not be a noticeable problem for FM reception - particularly if you live in an area where the local signals are fairly strong anyway, such as is the case in a large city. This is why you probably find the FM signal good, but the AM signal sucks. (By the way, your FM reception will improve with this fix, too.)

Best of luck.

Interference from spurious radio frequency sources is inherent in AM radio technology. This is a main reason why when very high frequency equipment became available in the early 1950s FM transmission was inaugurated. It is also why on your TV set the picture (AM) may become snowy while the sound (FM) remains ok (air TV, not usually cable).

Is the whining associated with your own car? Do you get it when only when your engine is running and does it change pitch or character with the engine speed? If so you might have poor connections or worn parts in your ignition system or alternator. If not related to engine speed, it could come from another accessory like your wiper or fan motor or fuel pump. Historically ignition units, voltage regulators, etc. had suppression capacitors to minimize this problem. Some cars manufacturers offer (sell) suppression kits to customers who have complaints (I don't know if Volvo does).

I seem to notice AM interference mostly when a much older car or motorcycle is nearby, in particular "electrically hostile" locations, and of course during lightning storms.