Toyota Repair: 1998 Camry A/C light flashing, drive belts, service history

Question
Today while driving the a/c light started flashing and the cool air became warm and the car fogged up pretty bad (it was raining).  I have an appt. with the dealership tomorrow for a diagnostic test.  Is this what is needed to find the problem?  

Also, I have never had the car tuned up.  I have done oil changes every 6 or 7K miles and the transmission done 2 times.  The car now has 105,000 miles on it. it's a 4cly, 1998 camry. I have never had a problem until now with the a/c. Along with the a/c the start up in the morning is a bit on the sluggish side. What is considered important to do for a tune up....spark plugs, belts?  The package the dealership has is mainly "checking" things and they charge $400.00 just for that....nothing major is included in that.

Thanks for the help/suggestions.

Cheri

Answer
There is possibly a leak in the a/c system, have the dealer check for this, there may be another problem, the only way to find out what that may be is to hook up pressure gauges and see what the problem may be, it may just need to be serviced.
I don't know what the service history is of this car, but it sounds like the timing belt and drive belts may need to be replaced, a tune up, consisting of spark plugs, air filter, fuel filter, oil change, transmission fluid and coolant change may be a good idea at this mileage,