The ABS unit on a 5th gen Accord sits right behind the driver's headlight assembly. There's a rubber plug on the top about the size of a quarter (probably gray in color). that's where you fill the reservoir. Keep in mind there is a bulletin on this generation Accord, where the ABS unit leaks, and that's why the reservoir keeps going dry. It involves loosening and retightening some of the plugs on the ABS unit. I don't recommend you try and do this yourself, because it's a bitch. I've done a few at work...NOT easy.