Defrost comes out the front vents

Check for a vacuum leak the vacuum motor may not be getting vacuum or it is no good or a leak in line. See picture for diagram on where to check.

Forgot it, sorry.

Is this automatic temperature where you set the temperature? This is behind the dash some you may be able to just feel around to find it to see if a vacuum line is off or motor is working you may have to pull out glove box or a panel under to reach it.

Ok if you set the temp it's a whole new ball game. See pic on how to test you may have to pull control panel out if you can't reach wires behind. This is for no air coming out a/c vents which from what I read is your complaint.

Check the vacuum motors in arrow one may be under hood to access the top two try pulling glove box and panel below dash. You may have to pull dash to acces these check for no vacuum or motor bad. Item 46 and 48 these control air direction in hvac unit.