I have a 2003 Honda Odyssey EX. The problem that im having is that my air conditioning just stopped bowing out cold air. It blows air and thats it! I watched a couple of videos from this link that showed how to do it yourself, because all of the people were having the same problem with the AC not blowing cold air. I decided to do like everyone else and purchase a "transistor assembly" from a local Honda dealer. I followed all steps (very easy). After i finished installing the part back into the original spot. I turned on the AC to see if it had worked and nothing! What am i doing wrong? Don't want to get ripped off by the dealers.

SOURCE: AC STOPPED BLOWING COLD; ONLY BLOWS ON MAX MANUAL SETTING

Your AC is low on refrigerant; The AC compressor needs a minimum amount of regrigerant to run. If and when it does run (while low on refrigerant) the air coming out of the vents will not be cold. The refrigerant you require is R-134A and is available over the counter but if you are the least bit unsure as to how to add refrigerant, taking it to a garage that does AC recharging would be your best play. If you want to try to add refrigerant on your own you will need the following, 1LB can of R-134A, an AC hose adapter to deliver the refrigerant, and preferably an AC pressure guage to ensure you are not overfilling the AC line which will damage the system.

SOURCE: I have a 2001 Honda Odyssey. I only recently

I've have never heard of a "only cold air system", but hey, nothing surprises me anymore. try replacing the control unit in the front. hopefully that will take care of the problem. If not you need to check your blend valve. (headache depending on location)