AC works randomly

We have a 95 APV that the AC works sometimes and then others it just blows at the defrost and feet. When this happens the ac clutch is engaged but the air doesn't feel cold. IF we turn it off for a bit it will start blowing out the right vents and be cool not cold. I have no problem working on the ac part but when it comes to the inside controls I have no clue.

Anyone have any ideas?

A bit confusing: you mean that the a/c compressor works OK, but the air is not directed where you want it, or it may be partly blended with heated air......or else..???
ANyway...an improperly loaded a/c cooling system will generally cool at first, then loose pressure...so a pressure check of the a/c system would make the case on that option.
If just directing air to the proper outlet is the problem, check for vacuum losses at the control valves, under glove box, lower left below
www.avigex.ca/xport/convenience_photo.jpg
is this a 3.1 or 3.8 as compressor is not the same and electrical control is different.

no, it will start blowing from the defrost but the air is still cool but it is mixing with the warm air from outside. It will switch back and work fine for a while.

Now that it is winter I was having the same problem with the heat. It would be warm then all the suddon it would cool off because it was mixing with the outside air. I think I have fixed it. I replaced the thermostat and it has not switched one time since I've done it. It would do it on a regular basis before this fix. I will see if it works in the summer when it warms up.