Help! Weird wiring issue with turn signals and head unit

[redplanet2001]

Hazards, turn signal and horn do not work on 2002 4Runner. Previous owner said they stopped working after breaking the antenna wire trying to replace the antenna. It looks like they plugged the hazard wiring harness into the port on the back of the head unit next to where the antenna wire would go. In videos I saw of stock head units being removed, this port was left empty and two cords plugged in instead. If I remove this wiring harness from the head unit, the speakers blast a loud constant noise. Any ideas?

 

[spartacus]

Hazards, turn signal and horn do not work on 2002 4Runner. Previous owner said they stopped working after breaking the antenna wire trying to replace the antenna. It looks like they plugged the hazard wiring harness into the port on the back of the head unit next to where the antenna wire would go. In videos I saw of stock head units being removed, this port was left empty and two cords plugged in instead. If I remove this wiring harness from the head unit, the speakers blast a loud constant noise. Any ideas?

Hazard switch plugged in?

 

[AntleredRuin]

Take the head-unit completely out of the equation for now. If it's helpful, completely remove it AND the amplifier that is separately mounted behind the head unit. The truck will operate fine with no head-unit plugged in. The stock radio cables plug into the amp, and then the amp plugs into the head-unit. Aftermarket radios will not use the stock amp; the whole thing is removed and uses the cords straight from the wiring hardness itself (with the proper Toyota adapter). There are 2 antenna cables that run to the stock head-unit. It's pretty obvious what they are as they are not part of the overall plug.



Focus solely on the plugs for the rest of the dash bezel right now. There is a blank plug in the dash bezel that throws everyone off. You may think you plugged back in your hazard lights, but actually just plugged into an empty slot.
If the hazards are not plugged in, then neither will the turn signals and a number of other lights.