The Master Caution - Air Cond will annunciate for a number of reasons. AS you correctly identified, Pack - either a dual controller fault or a trip off due to overheat.
Bleed - SOV closes due to an overpressure or overheat.
Both Pack and Bleed overheat and Bleed overpressure scenarios can potentially be reset after reconfiguring, however this may not always be the root of the problem.
Other scenarios would be Dual Bleed (two bleed sources ON i.e. engine bleeds and APU bleed), OFF Scheduled Descent (where your programmed cruise altitude in the pressurisation system hasn't been reached and descent was initiated) ,Zone Temp (again this time temperature controller related or a leak in a specific zone supply duct i.e flightdeck or cabin) and Wing Body Overheat (leak in the wing supply duct which supplies bleed air to the anti ice system)
Think that's it