Parts ID Please.

[SeniorTIKI]

Need help to identify a part. 2001 GMC 2500HD crew cab. Opened the drivers door and found this rubber part laying inside of the rear bottom of the front fender below the bottom door hinge. I checked the passenger side and found the same part in the same spot on that side. It looks like a shim or rubber mount of some type. Any help? Thanks

[C/K Man]

That is a flap that goes on either end of the cowl vent at the base of the windshield.  Normally you can't see it because it is behind the fender.  It is supposed to let water out of the cowl but keep hot air from the engine compartment from being drawn into the HVAC.  It has a little weight on it to keep it closed.    

[SeniorTIKI]

20 hours ago, C/K Man said:

That is a flap that goes on either end of the cowl vent at the base of the windshield.  Normally you can't see it because it is behind the fender.  It is supposed to let water out of the cowl but keep hot air from the engine compartment from being drawn into the HVAC.  It has a little weight on it to keep it closed.    

Thanks for the reply and info.