2018 Suburban LT Liftgate problem

[OR VietVet]

I am going to my friend's shop later today to have him plug in his scanner. He has a scanner that can do this.

@Doubeleive, the owner said he was experiencing an intermittent jerky motion and noises before the complete failure of the lift. Intermittent operation without the noises tells me an actuator problem but the noises make me think it is the lift struts. Maybe both should be done. Plenty of videos out there for the replacement procedures. I am going to question the owner with more detailed questions, after doing all this research. I do appreciate everyone's help too.

This guy is my girl's landlord and he was on the fence about me wrenching in the driveway when I asked for permission. Now he is completely on board since I work on his vehicle, his wife's vehicle, his son's vehicles and his golfing buddies vehicles. I actually have about a dozen vehicles in my neighborhood area that I have laid hands on. My neighbors are not afraid of the 6'4" tall and close to 300 lbs. grey hair and big beard deep voice Sasquatch lookin' guy in the neighborhood. They were standoffish at first. Even got some atta boys when I saw a homeless guy rummaging thru the trash cans at the curb of all the homes, looking for cans, and I ran the guy off and let him know to come back would be at his own peril. The street is a dead end and that helps make it easier to watch and we all watch. It is an upscale neighborhood but still see homeless a few blocks away on the main through road and they wonder around sometimes. All neighbors know I carry as well.

 

[gooffeyguy]

Thanks for explaining in that last paragraph, I know we were all wondering about it.

 

[OR VietVet]

Ha Ha, I get it. The jest is that I want to keep this guy happy, LANDLORD. Her rent is low for this area and the more he is happy, the lower the rent stays. Plus, he does pay me my going fee of $75 an hour for my labor. In this neighborhood, this landlord owns 6 homes. This dead end street is one of only two in the entire area. I like it back here.

 

[intheburbs]

Does the lock actuator trigger something in a motor that actually lifts and closes the liftgate? I would assume the lock actuator would do just that, lock and unlock. I am confused how that would then lift the liftgate? But, as you said about yours, the liftgate does unlock when you squeeze the button at the rear handle and does push away just a bit but then after that, everything is manual operation.

Can you post any links for the research you did? I look and all I see is parts replacement videos but nothing about diagnosing the problem. Thanks.

The lift/lower mechanism is the separate arm on the driver's side of the tailgate. Circled item pictured below. The struts are just your basic gas shocks. The arm does the actual lifting/closing.

I didn't save any of my searches, just went down a rabbit hole of Googling. The actuator/lock, the piece I replaced, must send some kind of signal to the lift motor to raise or lower the tailgate. Obviously, that wasn't happening. I do have a Tech 2, but I haven't played/learned with it much, and couldn't discern anything wrong digging into it.

So replacing the actuator/lock was an educated guess, hence my reluctance to spend $$$ on the Delco unit. But replacing it fixed the problem completely. Operates as good as new.

 

[OR VietVet]

The lift/lower mechanism is the separate arm on the driver's side of the tailgate. Circled item pictured below. The struts are just your basic gas shocks. The arm does the actual lifting/closing.

I didn't save any of my searches, just went down a rabbit hole of Googling. The actuator/lock, the piece I replaced, must send some kind of signal to the lift motor to raise or lower the tailgate. Obviously, that wasn't happening. I do have a Tech 2, but I haven't played/learned with it much, and couldn't discern anything wrong digging into it.

So replacing the actuator/lock was an educated guess, hence my reluctance to spend $$$ on the Delco unit. But replacing it fixed the problem completely. Operates as good as new.

I will look but on the 2018 Suburban, I don't remember seeing that arm. The two struts are beefier and as said earlier, I believe there is a cork screw effect in the driver's side, left strut. Maybe, just maybe, that lock actuator does still send the signal for the left strut to push up or pull down the liftgate. Thanks for the info and the pic.

 

[intheburbs]

I will look but on the 2018 Suburban, I don't remember seeing that arm. The two struts are beefier and as said earlier, I believe there is a cork screw effect in the driver's side, left strut. Maybe, just maybe, that lock actuator does still send the signal for the left strut to push up or pull down the liftgate. Thanks for the info and the pic.

Yup, different system. My bad.

 

[OR VietVet]

Attached scanner and there were no codes. Key in and turned to KOEO and the DIC showed the rear hatch open, because it was, so we knew the communication was there. Popped open the "umbilical" cord flexible conduit for all the pass thru wiring and that looked pristine. Ordered in new rear struts for the power liftgate. When they get here and if my girl is back from Texas, I will try to do a video of the struts replacement procedure. The ones I looked at on you tube are haphazard at best.

 

[Doubeleive]

Attached scanner and there were no codes. Key in and turned to KOEO and the DIC showed the rear hatch open, because it was, so we knew the communication was there. Popped open the "umbilical" cord flexible conduit for all the pass thru wiring and that looked pristine. Ordered in new rear struts for the power liftgate. When they get here and if my girl is back from Texas, I will try to do a video of the struts replacement procedure. The ones I looked at on you tube are haphazard at best.

the scanner did not have a option to command the hatch open/close?

 

[OR VietVet]

the scanner did not have a option to command the hatch open/close?

No it did not. I was looking over the shoulder of my friend that was doing this.

 

[OR VietVet]

Does anyone know if I have to have anything programmed/linked after these new strut assemblies are installed? I would assume not since the left one just gets a signal to move up or down but hell, I don't know. Thanks in advance.