Leaking still

[RegisteredUser]

Hey guys,
I have a water leak, still. Last year it blew out my blower motor relay, water got inside it and I had to replace it. I cleaned out the entire upper vent area of leaves and gunk, but noticed there's a big hole in the body.

I'm wondering if this hole is normal? ?? or if it's supposed to be closed off by something.

If I remove the blower motor, reach my hand up and forward toward the engine of the car (up and behind the glove box) there's a rectangular hole/opening where I believe water can leak into the car.

Is this hole normal? I would try to close it up but there's no easy way to get to it, just my hand can reach it. maybe some spray-in foam or something would seal it up.

My carpet is soaked mostly on passenger side which is the side where that gaping hole is up above the blower motor for the heater, it's only rain water no antifreeze, headliner rotted out from moisture, I have another headliner to replace it with but not going to until the leak is solved. Radio died from water damage so I had to pull it out.

The heater vent is set in the off and closed position, I read somewhere it could be a leak coming in if the heater vents weren't closed but it's leaking like crazy even closed.

I don't know how to find this leak other than to assume it's coming in from that rectangular hole. I'd like to patch it up but first get an idea from you guys.

Thanks a bunch, will probably buy a car cover for now.

[1990GTturbo]

The rectangular hole is where fresh air comes into the car from under the wiper cowl. If you have a sunroof check your drains as they run down the inside of the car and drain out inside the front fender below the door. You shouldn't get any water leaking through the fresh air vent unless you have rust built up somewhere. Ideally you'd want to pull the wiper cowl out and check the whole area over for rust. Odds are its a plugged up sunroof drain (if you have one) and you can just use an air compressor to blow the blockage out. Also check around your windshield for rust. I found quite a bit on my car when I was building it and I went through and cleaned/sealed all of it before having a new windshield put in.

[RegisteredUser]

I don't have a sunroof.
I've already taken the cowl off and cleaned it really well under there. It's a mystery leak.

[J_Unit]

Man that's tough. I'd probably remove the dash so you can see what's up.

[oldcarguy]

I don't think you have to take the dash out to fix your leak. I would check the vents on the
passenger side cowl and make sure they are sealed correctly. Most fixes I've seen involve butyl strips or in some cases I've seen clear RTV used. Good luck with your repair.