Check to make sure the green plastic vacuum line in the engine compartment is connected -- AC out the defrost is often caused by a lack of vac to run the system.
If you have a hand vac pump, attach it and see the green line holds vac. If not, you have a leak somewhere under the dash, if it does, you have a supply problems, look for broken hoses.
Tinting the windows shouldn't have done anything to the climate control, so I suspect it's coincidence.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!