SOLVED! 2007 Airbag Lamp Stays On & Codes B0058 & B0065

[LikeEnvoy]

My airbag lamp just started staying on steady (after the initial flashing when ignition is turned on).
I checked with a Viecar OBDII adapter and my cellphone running ChevroSys Free.
This app has SRS ans ABS tests as well as engine DTCs.
It returns codes B0058 and B0065 both current and in history.

I disconnected the larger connectors under the seat fronts and they looked clean and no visible wires loose.
I also removed the airbag fuse and after 10 minutes I disconnected a connector behind the passenger seat side cover; it connects to a spring loaded device where the seat belt loops around it. Not sure what this is for but the driver's side does not have this.
Anyway this looked clean as well and no wires loose.

The codes seems to be for both pre-tensioners having open loops. I didn't know I had pre-tensioners.

Anyone had this and know what is causing it?

The only work I have done recently is yesterday I changed the Mode actuator on the HVAC, so had the dashboard loosened and lifted half way. I removed the passenger airbag connector but reconnected it properly afterwards. I had the bolts under the passenger airbag removed too but don't see any of that would affect pre-tensioners. I had the battery disconnected all day while working on that actuator.

 

[TollKeeper]

@TJBaker57 - This I think might be one for you.. You talked about it some on the old site.

I think for this one, you might need a Tech2 to communicate with the items in question, and get detailed results as to what the problems are.

Seems to be common about wiring, but I cant see how you would loose both at the same time.

 

[azswiss]

I believe @TJBaker is going to be incommunicado for a while as he is doing some long distance hiking.

https://gmtnation.com/forums/threads/what-are-you-doing-today-part-ii.21812/page-23#post-625515

 

[Mooseman]

I'd be getting the schematics (check the link to the manuals in my signature) and trace the wires to the module. If both went at the same time, I'm thinking a ground let go.

 

[LikeEnvoy]

Ah- Good idea- I wondered about both seats going at once. I'll check the grounding after looking at schematics. Thanks Moose and TJ (That's some serious hiking, TJ !)

 

[LikeEnvoy]

p.s. The 2008 TB manual download is being flagged by my McAffee as a potential risk. When I tell it to download anyway, it's only 401 bytes and has nothing in it.

 

[Mooseman]

My browser (FireFox) also had security issues and doesn't ask for the password properly. I tried it in Edge and Chrome and Malwarebytes tried to block it however, once you allow it, it will ask for the password and downloads normally.

 

[LikeEnvoy]

(ah- I was using Firefox too)
I'm still looking into this problem. Checked the only ground mentioned for SRS system (just behind front fusebox) and that's good. The seat buckle switches work, so that's a good sign that the ground for the module is ok too. I disconnected the battery again and removed the plug to the Airbag SDM. all looks clean and no loose wires. When a passsenger sits in the right seat, the rearview mirror says "Passenger airbag ON", so it recognises that.

The pre-tensioner connectors seem to have only two wires: lo control and hi control, so no direct ground at those connectors. So far still a puzzle, especially because both seats are reporting a problem at once and it happened instantly when I drove the truck yesterday.

 

[Mooseman]

Could be the module but it is rare. I hate shotgunning but if you have a pick n pull yard you could get one cheap.

Anything in the wiring diagram that would have something in common to both, like a comme wire?

 

[LikeEnvoy]

Yup- may have to try a module if I get nowhere. Can't see anything in common except the module - ha. The main ground of the module traces to ground nicely.
The wiring schematic indicates the two seat pre-tensioners go directly to the Airbag module (SDM). Today I pulled the airbag fuse and after a minute disconnected the passenger seat yellow plug and the SDM connector.
I checked continuity from each of the two wires to the SDM connector- nothing- no continuity.
Same with the driver seat.

When I pulled the larger seat connector and checked for codes they all showed up: Passenger presence sensor fault, belt tension sensor fault etc. and when reconnected and scanned again they cleared, so those other wires under the seat are obviously not broken.

So, how four specific wires can all break, and on two seats, all at once, is a mystery so far.
Tomorrow I will have to pull one seat out and follow the seat wires under the carpet.

The schematics would have been more helpful if they also showed exactly where the wires route, but there you are. Hopefully a common point of problem may turn up as I unwrap the harness and trace the wires through (sigh of despair).

 

[LikeEnvoy]

SOLVED! Ok it was my mistake- but maybe this will help others from a bothersome problem.
There IS a common connector for both seat belt pre-tensioners after all. It's C202 and is mounted on the passenger-side lower trim panel (under the glovebox).
I didn't spot it because it's NOT yellow. All Airbag/SRS connectors are supposed to be yellow, but not this one. See attached picture.


















To arrive here, I learned that the 2007 service manuals do not have nearly as many PDFs as the other years and the "wiring" document for 2007 has only theoretical schematics- they do not show all connectors in the path. That's why I was stuck- it showed no common connector for both seats, only a diret connection to the SDM module.
However, the 2008 (and 2006) manuals have many more documents that focus on specific systems. The Airbag /Supplemental Restraints document has lots of details and diagrams that include all connectors in the path. So I spotted C202 in common and looked at the wire colours.
I then looked in the "electrical component locations" document to find C202 and found it indicated in Fig 112. It showed it was behind the glovebox. That's when the apple dropped on my head!
I had added some optional connectors and wiring a few years ago and I knew there were several black connectors in there that look the same at a glance but do not connect to anything at this time. So when I reassembled the dash after replacing the HVAC Mode Actuator, I simply thought these were all not used and left them alone. Duh! That one black connector should have been assembled.

The strange thing is that there IS a yellow connector under there but it has never been used while I have had the car. Figures, eh? The yellow one that you think should be important is not needed, but that insignificant looking black one is VERY important.'
If you get this problem please check that connector C202.

Thanks again for all suggestions- especially to look for a common connection!

 

[TollKeeper]

Is the yellow connector you are referring to the one under the black connector?

Thats the XM radio antenna connector.

 

[LikeEnvoy]

No, I meant the large yellow connector on the left. It's been there since I got the truck and is clearly not used. Sure looks like an airbag connector. The passenger airbag connector is way above this and is, of course, connected to the airbag. Weird. Maybe for the option of roof rail side-impact airbags they plugged in here?

 

[TollKeeper]

Or a knee bolster air bag, which I dont think any GMT360 got.