DIY: '20-up Harman Base Audio / OEM Door Speaker Amp Re-Integration

[FR-S2GT86]

Originally Posted by 86-75309

Another satisfied customer! I just finished the harness installation and now the system sounds like an OEM audio system should. It won't win any awards, but it went from "Are they kidding?" to "I can live with it."
Other observations:
De-pinning the connectors was a bit finicky.
My soldering skills leave a lot to be desired. Maybe I can blame the soldering iron?
The 15A mini fuse I had on hand is not the low profile type needed in the fuse box, but I got it to work temporarily until I can get the correct one.

Glad you got it built, installed and working properly. I made sure to create this DIY so that anyone who has never even cut and stripped a wire before can complete it.

[FR-S2GT86]

Update 11-15-21:

Changed the title of this thread to specify that this DIY is for MODEL-YEAR 2020 and up, which was actually RELEASED in the year 2019. Also modified a few sentences in the first post related to this change.

I may make another change later on once we find out if the 2nd generation cars have this same issue or not. Hopefully, the issue will be formally addressed by Toyota and Harman. Time will tell.

[SVXdc]

Here's a suggestion that will simplify things:

The OEM head units activate the power antenna lead (and the amplifier trigger, in HUs that have it) the same time they receive +12V Accessory power. So instead of bothering with the antenna adapters, you can just tap into the +12V ACC wire (aftermarket wire color is RED).

Also, the wires on this combined "breakout" harness follow the car audio industry standard for all of the colors: https://ae64.com/10-6-pincombinedharness.htm

That harness is also useful if you'd like to add a subwoofer and/or amplifier(s) for any of the other speakers. Unlike the Scosche and Metra parts (and other lesser- or no-name brands), it has wires on all 16 pin positions, so it will retain both of the illumination(+) and (-) signals in cars that have both.

You can also use it to augment the factory amp in the trunk. You might want to re-pin the wires so that the aftermarket colors match the functions of the OEM amp's wiring (which is different than the HU's pin-outs).