OK. Here you go with a couple of pics. The first one shows the door you saw while looking into the blower motor housing. The diaphragm is located directly above the gas pedal. The throttle cable and pedal mount can also be seen in the pic:
This door swings upward to let air in from the blower. Almost like a motorcycle helmet shield lifts up.
The next one is if the vents under the wiper arms. The raised rectangle is the intake for the blower motor. The rest of that area drains water coming off the windshield: