My A/C doesn't cycle on and off, compressor just stays kicked in. I checked the pressure and it was a touch low so I put one of those small cans into the system. It is now in the safe range but still won't cycle out. It runs until it freezes off and airflow stops. I have been switching it to vent every few minutes to keep this from happening. What do you guys think is the problem?

What's the low side pressure and what the high side pressure? Possible you have a bad low pressure switch that not tripping out proper pressure. Like if you look at the low pressure gauge rthe R134a ring will tell you the output temp of the system.

I noticed on mine after I finally got it running it wouldnt cycle unless we put a fan in front of the condensor at idle, but my fan shroud is broken top and bottom so it wasnt getting much flow at idle.

Cycling on and off is bad. :duh:Even in Sanden manual for the compressor is states it should run solid typically but only cycle up to 1-2 times a minute tops. Constant cycling of the compressor is hard on the clutch and will do damage to it.