I recently purchased a used 2019 Silverado RST with the integrated trailer brake and controller. I plugged my camper's 7 pin in and all lights and such work. However, the trailer brake does not work. I can't adjust the gain and the light showing a trailer connected isn't on. It also doesn't show a trailer is connected on my dash. I'm assuming the factory brake controller is bad but any info would be greatly appreciated. I've checked the fuses and none are bad.