I've got a 1994 Mustang 3.8 and when I turn on the A/C or Vent, the air
blows out where the defroster air should blow (top of dash on
windshield). The defroster works fine, and the heater blows out on
the floor, but I can't get air to blow out the vents where the A/C
should normally blow out (directly at passengers).
What's the deal?
The vent system is vacuum operated and if a line comes loose, it
defaults to defrost position as a failsafe. Check for a disconnected
vacuum line on the firewall next to hood hinge. Same thing happened on
my 93; vacuum line was hanging loose; when I plugged it back in, all
I found the place where all the hoses connect near the hood hinge, but
none are loose. Now what? I assume one of the hoses is loose at the
other end, but which one to check first? And how? Do I need to
disassemble the dash?
Hmm, if you don't see anything loose at the firewall, try to follow
each line coming out of that manifold and see where it leads; it may
have a break or split in it or it may be loose at the other end. Sorry
I can't be of more help; there are plenty here in the group who are
more experienced than me.
Also do a google search in this group for "defrost vacuum"
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