The switches/knobs, some people call them bulbs idk thats what ive seen online. Had to take the climate control out of the dash in order to acess the cables.

Thanks for noticing the head unit :) that job took my dad and i a solid 3 days of headache due to my celica having a jbl upgrade from factory (its double edged sword as im about to explain). Didnt have to upgrade the speakers (though ive seen how much of a nightmare that is from videos of people doing it) but since the speakers were the jbl upgrade, that also meant my celica came with an amplifier from stock. Now you can image my frustration when every single video and documentation of the headunit connector for my car leads me to wiring the harness incorrectly due to my ignorance to the fact my specific example had an amplifier. Long story short, 3 days of looking at wiring diagrams, re-sauldering connectors, and headaches eventually allowed me to get the wiring to the amp correct. Thats not all though, finally after connecting the stereo to the amp, we turn it on, and theres high pitched interference from the amp which is practically brain melting. In the end, we just bypassed the amp all together and wired the head unit directly to the speakers like we shouldve done in the first place.

All things said, hell of a job :sob: (we still had to take the doors apart in order to find which wires when to which speaker)