Chevrolet Repair: s-10 blazer heater promlems, airflow control, control doors

Question
hello, i have a 1991 s10-tahoe 4 wheel blazer
the heater only blows warm air out of bottom vents. limited air out of defroster. nothing out of dash vents. also hear slight air /vacum leak comming from dash. i live in northeast ohio and temps are in the TEENS!. can you please give me some direction on solving this. FROZEN IN OHIO.

Answer
Hi John,
Finding that leak is going to be what is needed first. All the heater airflow control doors depend on that vacuum.
You can get about three feet of garden hose, and while holding one end to your ear, move the other end under the dash, as you operate the controls, or just when you hear the leak.
The garden hose will act as a stethescope, and help locate it.

You could have a vacuum hose off, or split, or the control valve could be leaking.

Van