I'm putting this in General discussion to throw as wide a net as possible on as many forums as possible. We have a pampered and unmolested 2003 V40 that we love with about 104K miles. About 5000 miles ago, it developed a harsh, loud and persistent rattle and clank coming from behind the glove box surround where the air bag lives. I have taken everything apart from the front (radio, speakers, a/c control panel. etc.), except remove the dash itself, which is beyond my skills and abilities. I have probed around in the open spots with my hand, hoping to find a loose connector, or cross brace, etc. without success. I have also gone over the suspension and replaced the sway bar links hoping it might be those.

Is there any kind of work around to get in back of the air bag unit without removing the dash completely? And does anyone have an idea as to specifically what this might be? It's really driving us nuts! Otherwise the car is as quiet as an empty church.

I had a dash rattle in my 1998 V70. I finally took the dash top speaker grill off and found the speaker magnet had fallen off!!
a little glue fixed it.
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Keeping it running is better than buying new

Check also for broken motor mounts, especially the the one under the crankshaft pulley and the other, high on the firewall.

Have you checked the strut mounts condition? These can make a lot of noise when bad and can go unnoticed. Look for cracks, damage and looseness. You can easily test them by putting a wrench on the upper mounting nut and turning. It should turn/twist a little. However, if it turns easily the mount is toast.
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Will I buy another Volvo??? We'll see....