My 98 V70 had the similar problem until the speaker refused to work at all.

Tapping it didn't help any more. I found that the flexible wire that connects from the speaker terminal to the speaker coil broke under the normal vibration (it looked fine to the naked eye) of the speaker. I was able to re-connect at a lower point and presto, no more problems.

Now, this is a difficult task to do. In your case, you can just swap the speaker with a known good one a see if that cures the problem.

I just fixed mine. What happened was that I had to remove the radio, take off the cover. On the inside there is a small white connector block that attaches behind the volume knob. I pulled mine out from the circuit board, it just unplugs...and very slightly bent the 4 prongs going into it..apart just a tad. I plugged it back in and it works fine. Seems that the connector sits there and gets loose over time. It will take about a half hour to fix. I expect mine to loosen up again, then I will put a more permanent fix like either soldering straight, or something else. Just 1 little 4 prong connector that goes into the volume circuit board just behind the knob. Good luck, let me know how it worked.

Clarification: does the speaker cut out *entirely* or *mostly*? In my case, it's the latter -- you can still hear the signal but its volume is reduced and the sound is fuzzy (if you're not sure, the fader/balance controls will help you figure it out).

If this is you, then the answer is a resounding "Yup". This has dogged my '98 V70 since I acquired it. The first two times this happened to me (once to the LHD, once to the RHD), the car was under warranty and the dealer swapped out the speakers. This seemed strange since the symptom points squarely at an electrical issue, but when I asked about it, I was informed that the speakers were "tested and found to be defective". It began again recently, and with the car no longer under warranty and the dealer refusing to help (the answer to your question is "no"), I began experimenting more carefully with the problem.

I've noted the following: 1) if you crank the volume, the speaker always cuts back in for a time; 2) whacking the door doesn't seem to help, but opening/closing it normally sometimes does; 3) the problem is generally worse on humid or chilly days.

All of which screams "electrical problem", as I originally thought. These are all hallmarks of resistance fluctuation! But I bet if I popped the door cover, I'd see an intact set of speaker connections -- a truly loose connection should behave differently (i.e. would likely cut out going over bumps, would cut out completely instead of partially, etc.). So where's the problem? I bet it's either in the speaker internals or the spade terminals themselves. Maybe oxidization? Maybe crappy metal? Dunno.

Question: since the car is out of warranty, but this was done once under warranty at around 35k miles, will Volvo pick up the tab?

Answer: Hope will always triumph over experience..... but I'd be very surprised if they paid for something that they didn't have to pay for!

Q) has anyone else experienced this?

A.) Yes. I had one speaker replaced under the original warranty, too. Also driver's door. I understood from the service manager that failure of the LF speaker is not uncommon. Why? Perhaps because that door is slammed more than any of the others, and Volvo uses cheap speakers.

q) what fixes are known (other than the aforementioned "tapping")?

a.) Check the connections? Of course, while you're in there, it's just as easy to replace the speaker.

>>How hard is that door panel to take off and have a look-see inside?

The door panel is held in place by a number of plastic studs that are designed to be broken. (Rather than break the door panel.) Also a Torx screw or two. Buy a bunch of the plastic studs before you attempt this. This is a common mounting technique, wife's Honda also uses it. I understand there is a special tool available at auto parts shops to help with this, I just went ahead and broke the studs.

Good luck!

-Groundhog Phil