Q: My 2004 honda accord is making a loud chirping noise. Already replaced belt, tensioner, idler. What could it be

If it is a power steering pump, then the noise should change as you turn the steering wheel from lock to lock. If it is an alternator belt, the noise will likely change as you add or remove electrical loads like headlights or heater. You can also try turning the AC on and off to see if that affects the noise. High pitched noises can be difficult to locate because they seem to be coming from all directions. But one thing you can try is to get a 3’ piece of 1/4 inch plastic tube from the hardware store. Put one end in your ear and wave the other end around. You’ll find you have a very directional noise detector. VERY CAREFULLY point the hose at the locations you suspect the noise is coming from. You should be able to pin it down like this. If you decide to bring in help on this, contact YourMechanic. They can send a technician to your home or office to check out your chirping noise and let you know what is the solution.

I would first suggest removing the belts and see if noise goes away? If it does then check each pulley by hand to see if the power steering pump or the alternator is causing noise? If noise is still there after removing belt then you will need to replace the timing belt and water pump and tensioner for timing belt.