Can't go wrong with Metra products for after-market installation
2004 Toyota Sequoia
Crutchfield Customer Review (What's this?)
I only use Metra wiring harnesses for all my after-market installations. They clearly mark the critical wires (ground, power antenna, steering wheel controls, etc.) and provide a clear guide to the color coding on the remaining wires (which are usually like-to-like). Plus this harness had dual RCA outputs making the connection to the existing JBL amp in my 04 Sequoia a breeze to install.
Pros: Easy installation and Crutchfield threw it in to my order for free!!