Aaaaaaaayush

Check the basics first, make sure you have 12v power. Put a 12v light or a multi meter on the door lock supply you are using from the BCM and make sure you're getting power when pressing lock and unlock, also check the mirrors, using a 12v supply power the motors directly make sure they are actuating.

The door switches communicate using a canbus or GM LAN connection. When i changed my switch it did not work, not a single function. I tried many different things including soldering wires to the pad for the mirror fold button, but was not able to make a relay circuit that stayed on long enough to fold or unfold the mirrors. I did give up on the door switch and put my old one back.

This is correct, here are the connector end views so you know where the pins are.

Seriously! Or at least some likes on my posts

The pins from the BCM are going straight to the drivers door actuator(solenoid), these are the actual High Low signals for the actuator, no relay needed. I did this so that I can unlock and lock my bed mount toolbox from the OEM truck remote key fob. The current from these actuation signals should be plenty for a second actuator in parallel, as it has worked perfectly fine for my toolbox as well as the power folding mirrors. if the new actuator moves the wrong direction just reverse the polarity and it will move the other direction.

Haha I wish I had somebody to give me this information back then… pin 2 and 4 are actually for the drivers door lock actuator, I used these for a lock actuator inside my bed tool box so I can lock and unlock the toolbox from my remote just as you are trying to do for the tonneau cover. you can use the GM Upfitter or body builders manual to find these connectors and pin outs https://www.gmupfitter.com/wp-content/uploads/2021/05/20_Sierra_1500_Electrical_Body_Builder_2019JUN20.pdf pg.413 is where the BCM connectors start. good luck

https://www.gmupfitter.com/wp-content/uploads/2022/10/23_Silverado_1500_Electrical_Body_Builder_SM_en_US_2022OCT24.pdf 23_Silverado_1500_Electrical_Body_Builder_SM_en_US_2022OCT24.pdf Page 520/1192 I have not tested this, but its probably just a 12v dimming signal for the dome lights.

It hasn’t had any problems except for when the mirrors were iced up I would just break them free and they would operate as normal

Side Rearview Mirror Auto Fold Unfold Controller，Mirror Closer Modules Folding Closer Module Universal Replacement for 12V Car https://www.amazon.com/dp/B0925NT3KB/ref=cm_sw_r_cp_api_i_BA3Z7RJWPJBRBDEZP0XC?_encoding=UTF8&psc=1

one million billion dollars haha

The multiflex isn’t available qt6. I think it’s just too heavy for the motor with all the extra hinges and latches. It would be a cool project to diy OEM style and make it work. Start with a used(already programmed) module and a harness and try to put in your own actuator motor maybe a higher torque motor to lift the extra weight. You’ll have to custom fabricate motor mounts and the shaft to body connections. Good luck

The only other way to get in after an electro mechanical failure would be to remove the tailgate cover and pull on the latch release, I’ve done the qt6 tailgate mod previously and I had one problem where I couldn’t open it from any button or key press so I had to hop in the bed of the truck and take off the tailgate panel. If you have a cover that locks from the inside then you’re probably screwed if it fails, but I’ve had it for a while now and I’ve only had that one failure and it wasn’t anything inside the tailgate actually it was the connector under the bed that had somehow come loose.