Mystery of the spasmodic air conditioner

I have a 2003 Accord V6. Approximately 6 weeks ago, the AC worked in the AM, and blew hot air to the airport(40miles) in the afternoon. Mechanic said the system was 25% low,no leak was found, compressor checked out, so filled it up. Now, it will work in AM, not after work, or not work at all for a day or 2, then work in am, work in the afternoon, not work coming out of a store after 5 minutes. It seems to either blow very cold or very hot. Whats the deal?

[b]The AC compressor on your vehicle has a thermal limit switch mounted on it. This switch cuts power off to the compressor in the event the compressor begins run hot. This is a safety feature to prevent damage to the compressor.

It could be that this thermal limit switch is malfunctioning, thereby not allowing the compressor to operate under what would be considered normal conditions.