So I installed a new stereo. Soldered all the wires and plugged it in. It works fine… except there is no sound. I connect an outside speaker to the head unit any music came out. I have since installed the old radio back in the car, so the speakers are fine. I think there might be a stock amplifier inside the car I might have to wire around. Is anyone familiar with this? Where is it located in the car? Any other thing that could be wrong with it? This was supposed to take an hour; it’s been a week so far. Please Help

 

I think the 2004 Sonata had three factory options for the radio. Some used an amplifier, some didn't. Was your stock radio 2" or 4" tall? If it's 4" tall, then there is an amp that needs a supply lead (pin #12 ?) off the radio pigtail that turns the amp on when the radio is turned on. If the radio was 2" tall, I don't think the car had an amp in it from the factory.

 

ok... so i found the amp (it's the 4" tall radio). now how do i get power?

 

There should be a lead on the harness coming off the new radio labeled "AMP". You need to wire the new pigtail so that AMP lead from the new radio is connected to the same wire that was fed by pin #12 on the factory radio. Make sure you have all the grounds wire correctly.


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stock amp is in the trunk, pass side(quarter panel)