Chevy Corsica 1996

I was driving my 1996 chevy corsica 4cy automatic
with 106,000 miles on a hot day and I smelled
antifreeze. When I checked the radiator hosed
were ok so I checked under car and found antifreeze
all over the underneath and I saw a connection
coming out of the firewall near the passenger
side and antifreeze was leaking from it. There
was a rubber elbow on this connection and nothing
else. More towards the center of the firewalll
was two more connections intact with hoses on them
I took these as heater core ins and out.
I would like to know what you think this connection
is and how to fix it. Thanks glen367