AC evaporator questions

[MalcolmY]

A year ago I replaced the a compressor and receiver/drier after the compressor broke. The cold air wasn't as cold as it was before.

Recently I had a leak and got it fixed, the mechanics added freon but he didn't like that they compressor was on all the time, it didn't disconnect and reconnect. And he didn't like the temperature of the air coming out of the vents, neither did I. He said I should have replaced the condenser, expansion valve (or cleaned it if it could have been cleaned) and cleaned the evaporator.

So I have a few questions:

1. Could the evaporator be cleaned without taking out of the car? Are it's pipes cleaned from the inside usually (like a radiator) or the five from the outside?

2. For the 4th generation altima, is there any way around taking off the whole dash?

3. Where is the evaporator located?

3. Could the expansion valve be cleaned?

Thanks!