sup guys just happen the other day driving down the road kicked the a/c on an it started blowing from the defroster an it was on vent so i tryed floor an same thing just kept blowin from the defroster so then switched it to heat an did the same thing any ideas guys ?
This has got to be the most frequent problem that comes up on this website. All the control valves are vacuum operated, and defaults to the defrost vent when the vacuum fails. There is a vacuum tree on the inside fender on the driver's side. There is a small black vacuum line that runs from that vacuum tree across the firewall to the passenger side, and then through the firewall. 99% of the time, the vacuum to the HVAC fails because the heat of the engine bay caused that line to fall apart. Check for a leak or breakage on that line.
You have a broken vacuum line which opens the door for the A/C. Like Kurt mentioned is extremely common as the lines become old and brittle. I believe the A/C line might be right on the vacuum tree by the brake booster (the smaller line).
Yes and any vacuum line hose the same/correct size will be good. I mention correct as it's possible the hose has been replaced by a previous owner and may not be the right size.