Rocky Mountain At4

I can't seem to find the fuse for trailer accessory power if one exists, but the in-line fuse at the t connection is good and everything is plugged in. Seems like the unit itself may be toast.

My tailgate speaker worked fairly well before, but now I can't even get it to turn on. The connections and fuses seem ok unless I am missing one somewhere. Any ideas?

My truck also makes a lot of the same clicking noises when I open a door or shut the engine off. I don't think that is anything to worry about. Annoying, Yes. My truck seems to engage the parking brake all the time by itself.

I have a 2020 Sierra 1500 with about 4,000 miles on it and it easily has about three dozen rock chips already. That does not include all of the chips right behind the wheel wells towards to bottom of the body. I literally get about 10 new chips every time I drive on a dirt road. I have two F-150's before this with no noticeable issues. My truck is going to look horrible before winter even hits...

My 2020 at4 with 6.2l idles rough too. I only feed it premium gas, but it definitely seems unhappy at idle.

A quick update. GM engineers told me my truck was safe to drive with the aforementioned codes and said they are working on a fix. That did not make me happy, but whatever. Then today, the check engine light came on again and my transmission started going downhill fast. It started making hard, jerky shifts before it decided to shift into I would guess 3rd gear while I was doing 75 mph on the freeway. The rpms went to about 4500 instantly. I got off the freeway a d it did not shift out of that gear for the rest of the trip. After shutting it off and driving it again about 3 hours later it was shifting with major issues. At one point it would not advance gears and was just revving/bouncing off of one gear almost like I was hitting the rev limiter even though it was at about 3000 rpms. OnStar is showing codes P0700 and P2715 with the following description. The Engine and Transmission System is not performing as expected. An issue has been detected in the Transmission System that transfers power from the engine to the drive wheels. You may experience reduced power or shifting issues.If the vehicle is continually driven with the check engine light on, the emission controls might not work as well, the vehicle fuel economy might not be as good, and the engine might not run as smoothly. This could lead to future repairs. This truck is not drivable or safe. I will be going back to the dealership for the third time. I have just over 1200 miles on it now...

Truck is back with the dealer and they said the previous software update was supposed to fix the problem. They have escalated this with GM and are talking with their engineers. There is no fix yet.

Well, I got my truck back after they updated the brake control module with the new software and everything seemed good. Today I fired her up again and got an immediate check engine light. OnStar did a diagnostic report and showed that they "failed to probe" the ECM, SDM, TCM, BOI, and ABS system and could not read the check engine light codes. I will call the dealer tomorrow morning and get it back in. I was about to put a 1" front level kit on, but I am now thinking I need to hold off until they fix this issue. Anyone had success yet?

I also have these four codes and the CEL. It just came on today upon start up. My 2020 Sierra 1500 At4 only has 500 miles on it. The dealer said there is an update available for the braking system control module. Once I get it updated I will report back.