Guys,

I have galant 2004 DE 4 cylinder and wondering if i can do it myself to clean my A/C evaporator. I have read other forums for different types of vehicles that it is normal for vehicle to have some foul odor but steps must be taken to remove them. Also, please include if you can provide me information if i have to open the heater assembly to inject the fluid to clean my evaporator. I know the location of my blower and heater core and evaporator but i haven't take a look if there's a hole i can use to inject the evaporator core cleaner solution. Also, im wondering where is the air intake vent....
Any advise would be highly appreciated.

Probably the easiest way is to drop the glove box and unscrew and pop the clips on the panel behind the glove box. This accesses the blower fan case. In the top of that is a door, with key on set the heater/AC to "recirc". Now the door will be open and you can spray the AC freshener down into the blower fan with it running and controls set to max cold AC and it will circulate through the evaporator.

to make sure it's the right door, select between recirc and fresh and watch it swing back and forth.

while your in there might as well look at the cabin filter to see if it's dirty and needs replace (if it has one), it's right below the recirc door, in fact you should remove the filter temporarily, if it has one, for the freshener to circulate better.

a dirty cabin filter can cause smells

If a lot of leaves get through to the evaporator spraying freshener may not help, especially if the AC drain tube is clogged. It fills the case up with water and goes mildew city.

you can take a mirror and see if there's leaves down in the fan while the blower case is accessed.