My truck did not come with screw holes to mount defroster vents and I already had the dash painted and the windshield mounted so I glued the vents under the dash in place with POR 15 seam sealer. I have used it around AC connectors going through a inner fender panel and it is like epoxy and nearly impossibly to remove once it sets up.
TractormanBill

 

Did someone fill the original holes? I can't imagine it left the factory without them!

 

The truck did not come with a heater but the body man I had working in the cab must have filled them in even though I didn't see or feel any humps on the underside. Anyway I got those babies mounted.

 

Hope that you never have to remove them.

 

I glued mine also (a 49)make sure that the two piece drivers side tube is not glued you need the area where the tube connects to install the gauges and windshield wipers


I got a good one from firstrider