Fixing the defroster vent strip...
Just figured I'd post what I did to fix the wavy defroster vent in my '90 Bonneville'* dash.
It was straight when the car came here. But after only a few months in the Florida sun, the vent warped and popped out on the driver'* side and in the middle.
My solution, that seems to be working, was to reinforce the moulded vent with two pieces of 3/32nd music wire from the local hobby shop.
I took the vent out, turned it over, then drilled holed through the cast flanges/reinforcing ribs on the underside of the vents. Then inserted the music wire through the holes, which made the whole vent stiffer down it'* length.
After another week in the Florida sun, the warped vent has pretty much flattened itself back out and stays in the dash pad. The rods are visible if you are looking down at the dash through the windshield (looks like a extra pair of fins in the vents) so next time I have it out to work on the dash I'll paint the rods flat grey to blend them in.