I was looking through some of the photos on my phone.
For some unknowable reason the engineers at GM decided that a corner of the backside of the front of the dash next to the release cable for the emergency brake and behind several wire bundles would be a great place to hide the relay for the turn signals.
To even take the picture I just shoved my phone in a small area and took a bunch of photos. Most were just garbage, but I did find it. I have no idea how any normal man's hand can reach in there. I guess I will have to disassemble and remove the instrument panel and maybe reach it from above. No way can I get my hand in the there now.