Noisy vibration coming from the dash

lexus
300

#1

I have a Lexus GS-300 that I purchased for my darling 16 year old teenage daughter. The problem is we get a very loud vibrating noise that comes from the dash, intermittently, but often. Happens as we are driving down a flat road. All roads are flat in Houston. My friend says I need to find the right spot on the dash, and just hit it. I also heard you can turn the heat up to high to get rid of it. Well, I am hot enough living in Texas without turning the heat up. I tried banging the dash with my fist, and it has not worked. Plus people might think I am having a melt down (I might be having one with the darn heater on in 104 degree weather). The air conditioner started blowing out heat so I was hoping my mechanic could fix the noise problem while the dash is pulled out of the car. Dave at Goodyear said it could not be done. He has tried it on his own 2 Lexus’. This noise has to go. We try turning up the music but it is still very annoying. The beautiful 16 year old blonde will be much happier with Grandma’s car if we can get rid of the noise and vibration. Any ideas?