odor coming from vents

[OCSL]

I have a 98 sl it started giving off odd odor when I first start car then it seems to go away, also the AC will switch over to EC and not go out until I shut off car,Then one day the AC is ice cold and the next it blows warm air.This is what I have done so far: replaced cabin filter,sprayed wurt's cleaner in intake. seems to have helped a little.It has been suggested that I have AC evacuated and refill and also have evaporator cleaned.I won't fool with AC will have that done,can I get to the evaporator and clean that myself?