AC doesnt blow air all the time. I'll start it up no air, turn the car off and restart, blows air, doesnt do all the time. 2002 Lincoln Town Car Signature Series.

Something broken stay only on cold !!!

I'm no expert when it comes to your vehicle. However it sounds to me as though there may be a vacuum leak somewhere causing the HVAC door that controls the AC/heat to be faulting to the 'hot' side.

Drive the car up to 55 MPH with the AC on. Making sure there is no vehicles close behind you,completely let off the gas pedal and see if it starts blowing cold air right after letting off the throttle. If it blows cold, then it's probably a vacuum leak.

If it doesn't blow cold then it could simply be low on freon or a partially clogged filter in the AC line.

Hope this helps.

Check you blend door under the glove box see if its opening and closing

It sounds to me like yu are describing the symptoms of a broken blend-air door or blend air door actuator. In either of these cases, dash removal is required to repair it.

replace the clockspring

Could be the vacuum motor blend door problem where the plastic door inside the dashboard is not properly being angled to direct cold air and to block hot air from coming into the cabin.

it blows out hot air and the lines is hot

To fix the AC unit which blows hot air all the time. Seems like you have a small leak in the system or the AC compressor has gone out. Suggest you try recharging the unit. Make sure you have the correct R-22 or 134A freeon. If this work for a few days then have the leak fixed, if this doesn't work replace the compressor. Check Ebay for the compressor i obtained one for $100.00. Cost $450 at Auto Zone.

indicates a problem in the fan in front of the condenser
possible loose connection , bad relay or bad ground point

if you have checked the fuse and they are good and there is power going to the blower replace the blower you should be able to pick one up at a good salvage yard at half the cost.