My 95 ford escort a/c barely blows air

Looks like your mechanic messed up. If he has any integrity then he should take care of you. If not and you want to try and tackle it yourself then you have to ask yourself this: do I want to pull the dash out? Because that is what that will entail. Sounds like he may have messed up the ducting somehow. Unless the blend doors and directional doors are electric actuator operated in which case those actuators need to be replaced

1. Check if air blows with the fan setting turned to high.
2. Check that the radiator cooling fan engages when the A/C button is pressed.
3. Locate the compressor.
4. Turn on the A/C.
5. Check if the compressor's clutch has been engaged.
6. If the clutch engages, the fault is elsewhere.
7. If the clutch does not engage, check for power to the clutch.

These steps might help find the problem.

does the a/c get cool but not cold? if so then may just need some freon. check the low pressure side with the engine idling and blower set to high and on MAX a/c. the low pressure side should read between 35-45 psi , if it is lower than 35 then add 1 can of freon to see if pressure comes up , if it doesn't then you may have a weak compressor or a clogged orfice tube. but if the air is hot and not even cool the you may have a bad comprossor clutch, check to see if it is coming on.

Here's a site that will help you.
http://www.gmtruckclub.com/forum/threads/ac-heater-defrost-vent-problem.2511/
some exploration is coming...

the fan may have went out. what your feeling is air coming in as you drive. ford trick for fresh air lol. the fan needs to be tested to see if it has stopped working

replace the cabin air filters

vacuum line was off,and flushed heating core,

U have a short in your blower motor circuit. Have an electrician check out.

Sounds like your freon has leaked out and your heater blower resistor is burned out. Deffinitly take this to the dealer.

does the heater blow on different setting? i.e into the cabin?
if it does check the hose at the back of the dash hasnt come off and is stopping airflow to windscreen.