In my quest to make my car water tight, I have been making a lot of repairs and replacing seals. I noticed that if I run water directly on the driver side wiper arm where it goes into the cowl I get water leaking out of the HVAC box inside the car. I can only guess that the intake for the HVAC is below this area, and the plastic seal that goes around the wiper base is supposed to keep water out. In my case, the plastic "seal" as I am calling it is cracked in half. Does this sound correct? I also haven't been able to find this seal.

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1985 300D 296,000 miles - Project "Rusty" 1/4 mile in 19.9 sec @ 71mph. It's almost rust free and water proof!

2006 Dodge/Cummins 6-Speed - 670HP 1159ft/lbs