"An Example of Deaf Humor" joke

( This joke has been told by many deaf people and has been recorded in
a few books on deaf culture. The interpretation of this joke is mine,
though. )
A deaf couple checks into a motel very late at night. Upon moving into
their assigned room, they go to bed. But in the middle of the night, the
woman has a headache, so she goes into the bathroom for aspirin. But she
finds none, and remembers that the bottle of aspirin is still in the car.
Afraid to go out alone at night, she awakens her husband and asks him to
go get the aspirin from the car. The very groggy husband puts on his robe
and toddles wearily outside. He finds the bottle of the aspirin in the car's
glove compartment, and gets ready to go back to the room when he realizes
something: he can't remember which room was his!
He thinks and thinks and then gets an idea. He opens the car again and
honks the steering wheel horn several times. Within a minute, all the
motel's windows lighten up-except one window, and of course, he makes
for the room with that window.