Hello, sorry for your frustration. It sounds like there's an issue inside the TIPM (total integrated power module). It's basically a power box, and it runs almost everything. They have a high failure rate. You should start by checking the box for corrosion underneath and inside. The brake switch and the rear turn lamps are in the same connector going into the TIPM. So I would check the connections/plugs going into the TIPM. Also look in the area of the TIPM for any ground wires going to the body frame for corrosion. This issue can be caused by a faulty body control module or wiring issue to the BCM. The last picture is the body control module and it's inputs and outputs. The BCM picture came out blurry, so here's the area of the brake and turn signal circuits.
Images (Click to enlarge)
Monday, December 21st, 2020 AT 10:46 AM