[Rapid1]

This looks like the right place for this question. 2004 silverado, stock radio, using the fast system wiring with a BTA8100. Using the information here, I find that the only thing missing is the blue/white turn on signal. the thing is, there is no wire in the corresponding hole to it in the factory harness.

the radio interface harness part number is fast-2003 with a fast-btah connecting between that and the sub.

do I need a different interface harness?

first post and hey everyone.