2nd attempt – Metra 70-8113 – Fit one of the three factory JBL harnesses, and the new head unit powered on, however no sound. Found out part of my factory JBL system was an amp in the trunk that powers 10 speakers. This harness didn’t provide the necessary data signal to the amp to turn it on, so there was no sound.
https://www.amazon.com/Metra-TYTO-01-Amplifier-Interface-Harness/dp/B00133RCCC

