Since you don't have the plug under the dash, just the wire pigtails, you'll have to splice them to the end of the harness that comes with the P3 as shown in the video raspivey posted.
Here's the controller at etrailer:
Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional Tekonsha Brake Controller 90195
Fast delivery. I've got the same thing in my 2009 Silverado, only I had the connector under the dash. GM's gone cheap in the last couple of years.
You'll probably have to do the wiring thing at the fuse box, as shown in the video. (I had to buy the 2 nuts, different sizes, of course, and two fuses, one for brakes and one for the aux power.)
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2016 Mini Lite 2503S - tt (2015 - ???)
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2009 Silverado Ext Cab, 5.3L, 4x4, 3.73
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