Advice for Dash Rattle?

[illinoised]

The dealer (2 hours away) told me I had a defective catalytic convertor (5 K on my P5) which was causing a vibrating rattle in my dash (occurs only when accelerating from a dead stop, and about half the time I accelerate).
The new cat did nothing to alleviate the problem. They did take out the glover compartment and put back in (simple to do) but I'm sure they didn't take apart the dash to look for the source.
Any ideas on how to troubleshoot this?
Thanks in advance for suggestions.

[blue LEDz]

take it back to the dealer or have someone else drive you car while you listen for where the rattle is coming from.

[mixmaster_matt]

I have had this rattle for a long time and cannot find the cure for it, no matter what I do.

[Grocerygetter]

I have a similar type of rattle in my dash a very low vibration near the climate control switches. It annoys the piss outta me in the mornings It stops when I turn the fan all the way up and then off but only for a few minutes. My dealer hates me (three transmisions) so I have to take it elsewhere, live with it or tear aprt dash and find it I chose the latter still have lots of P.L.O. (parts left over)