I have an 03 Accord v6 coupe with nav. This particular issue has been a problem for years, off and on. I have had a Honda dealership and an indy look at it- both times they said the same thing, that I must not know how dual temperate zones work
Here's the situation. I've had the car for about 3.5 years, and for the first 2 or so the AC worked as it should- dual zone worked, and when they were both set to the same temp, all vents put out the same temperature air. Somewhere along the line, something has happened to where the passenger side vents now only put out ice cold air- like the right side of the car is stuck on the coldest AC setting while the driver's side functions normally. I can change the temp up and down the ladder, turn the ac on/off, change the air flow, etc.- same problem.
This happens probably 90% of the time, regardless of time of day or time of year. Obviously it has been quite problematic in the winters, but I've lived with it. The times that it does work as it should, it either starts out correctly once turned on, or will blow out cold air only for quite a while then finally switch over to the correct temp. I have read about issues with the a/c taking a while to start blowing the correct temp, but this is different IMO. It works as it should on the driver's side 100% of the time.
I've had bad luck googling an answer, and I would prefer to not go back to the dealership without giving them specific things to check. Any help would be greatly appreciated.