Hyundai I10 MUSIC SYSTEM NOT WORKING MAINLY SPEAKERS

Pending knowing year of the car, the best we can do is offer some common checkpoints.

The first thing I would check (and I am assuming you checked the basics like audio levels and settings, or reset it to factory before posting this) is if you can get an all-system scan tool, scan it, and look for any chassis audio codes—these will not show up on the generic codes, so you will more or less have to use a more advanced scan tool to see. You want to look for codes relating to the audio system to isolate the fault. Some cars do not do this, so it's not guaranteed, but some will show audio system codes.

You can easily do this at home even if you can't get the codes. Get a multimeter, and find the fuse for the radio and amp - it's usually on the driver side with Hyundai/Kia products, so start there. The fuse you want is probably not under the hood, as that holds the engine-related fuses, relays, and pyrofuses. Check both for continuity (the meter will beep or show something like this, indicating the fuses are good (Hint: Meter should read 0 in some form, as both of these are doing):

You do not need a Fluke meter like I have. I got mine from a shop that had 3 used/open box meters as a lot for about the price of a new one because they were closing for a very agreeable price. Get a Klein, Brymen (Either direct or through EEVBlog) or another well built meter.

If the fuses check out, I would inspect the speaker wiring in the car and make sure it is not damaged and well-connected; if you can track it down and check the resistance of the wire to make sure it isn't showing high resistance, that may not be a bad thing to check as well. If you can reseat it and look for corrosion (and clean it as needed), then reseat the connector;r this may very well be enough to catch the fault. If the wiring is good, then you have a deeper issue. If you have a more basic audio system like the base radio found in a lot of stripped US Hyundai/Kias, then the amp is in the radio - the preamp is bad, and you'll need to repair or replace the radio. If you have one of the higher-end systems like the ones found in the US Optima with the nav radio, it's probably a dedicated preamp given the system's complexity.