More than a year ago my AC/heater would stop functioning. The buttons just didn't respond anymore but the fan still ran. Button lights remain on. Full function would return usually during the next car trip. Weather didn't seem to matter. I found after several months that banging on the dashboard would get it to work again. The last time I did this was about 8 months ago. It has gone out only once since and for a few seconds. It is now winter and I am afraid that one day I will need the defroster and it will not function. I have been advised to replace the whole unit, but I am not convinced this is necessary. I have seen on the internet that this has happened to others with the Honda Accord. Installing a new unit at the dealers would be pricey.