08 Tahoe rear door lock inconsistent

[cozbback]

Hey all, new to forum as I just picked up a new to me 08 Tahoe LT with 190k on the clock. Wanted the room and the comfort from my previous ride, and this fit the bill. Mechanically, it looks to be all good, just need new brakes which I'll be working on as soon as I return from vacation. Otherwise some minor cosmetic issues (to me) and a few wants to be done so nothing too big.

I have noticed that my rear locks are inconsistent when they lock or unlock. Doesn't matter if I use the fob, the drivers door switch, or when it auto locks and unlocks in regards to the shifter going in or out of Park. Sometimes it works, sometimes it doesn't. And it's not just one door, it's both. If one locks, they'll both lock. If one doesn't, they both won't. Same with unlocking. No consistency on when it happens or doesn't either.

I'm thinking I need to replace both rear door lock actuators, but wanted to see if anyone had any knowledge to steer me elsewhere before I spent that money.

Thanks, and I look forward to a lot of information, builds, and fun times on this new adventure.

 

[89Suburban]

Hey all, new to forum as I just picked up a new to me 08 Tahoe LT with 190k on the clock. Wanted the room and the comfort from my previous ride, and this fit the bill. Mechanically, it looks to be all good, just need new brakes which I'll be working on as soon as I return from vacation. Otherwise some minor cosmetic issues (to me) and a few wants to be done so nothing too big.

I have noticed that my rear locks are inconsistent when they lock or unlock. Doesn't matter if I use the fob, the drivers door switch, or when it auto locks and unlocks in regards to the shifter going in or out of Park. Sometimes it works, sometimes it doesn't. And it's not just one door, it's both. If one locks, they'll both lock. If one doesn't, they both won't. Same with unlocking. No consistency on when it happens or doesn't either.

I'm thinking I need to replace both rear door lock actuators, but wanted to see if anyone had any knowledge to steer me elsewhere before I spent that money.

Thanks, and I look forward to a lot of information, builds, and fun times on this new adventure.

Welcome aboard. You are on the right track with replacing the actuators. Here are some tips in this thread about replacing them.

What did you do to your NNBS GMT900 Tahoe/Yukon Today?

Probably needs a new door lock actuator. Pretty common for those to go out. you are correct it has power to it and all linkages are connected

www.tahoeyukonforum.com

 

[Just Fishing]

Yup, as @89Suburban said.
Common thing.
I still need to do my driver's side, but the back or passenger side take priority.
the driver's side is getting much worse for me, and I'm about to get motivated to do it.
I still have the OEM unit sitting on the top of my toolbox taunting me.

Go OEM if possible, but the cheapie amazon units do work if your handy and willing to fiddle with things or do light modifications.

I don't know how the rears will be, but when i did the passenger side it looked like my arm and hand was attacked to a wild cat.

 

[swathdiver]

@cozbback A Tech-2 is an indispensable tool for quickly and accurately diagnosing problems with these trucks and making repairs. It will pay for itself in short order.

 

[Just Fishing]

^ true
Tech2 would allow you to actuate the door lock and and allow you to watch the data read out.

For my door lock problem, it's obvious to me there is an internal issue within the lock motor.

I can see and hear it trying.
I might look at it with the tech2 while it's acting up one day.
But in this case we already know the issue.

I also saw Gruven (i believe) sells gears to fix the door lock actuator.

I did try to dissemble my old front passenger door lock to see the internals/
issue and ran into many issues.

Mainly it's glued, crimped, and screwed together.

After i stabbed my self with a pick while messing with it, i said fk it and tossed It in the garbage.


The cheap $30 amazon lock i used on my passenger side has been working fine for a year or two now.
I will note that it has a different sound.

That one door closes with a "tinny" sound.
I think it's making slight contact with the door striker but it hasn't yet left a mark confirming it.

Otherwise it's fine.

Just my slight ear telling me something might be wrong with it everytime it closes.
Then i remember "oh yeah the cheap lock".

The oem new old stock was much more expensive.
Iirc i scored it for under $100

But they are available all day long over $100.
Maybe the rears are cheaper?

 

[cozbback]

Thanks all. I'll be attacking those when I return home from vacation. Weird thing is, I replaced all four handles, and the rear locks have been acting correct ever since. Of course it's only been a couple of days since I did that, so I'll be confirming later.

As for a Tech2, I just might look into that, but I'm also considering a programmer of some sort and will need to research what performs the same features for what I want to accomplish. That's something fore later.

Thanks again!