Man I was sitting in the truck on New Year’s Eve warming it up. Started hearing a sizzle/hissing sound, looked back saw a little smoke from the little box were the slider meets the passenger side window. Turn back to turn the rear defrost off and hear a Big Bang. ? This is my 17 Sierra AT
I am no tech but I only come up with the rear defrost or slider. From the picture u can see the break started from that slider connection.