This wire/short cause the air bag light?

Schmidty72 · August 31, 2013

This is supposed to be the place to get tough answers. Please stick with me, I'm not good at electrical stuff (fixing or explaining). Here is what happened...

I replaced the parking brake assembly in my 2006 Sierra (ext cab, 5.3 v8). That went in fine (mostly). I was in a hurry to do this job, and I screwed up. When I resembled, I pinched a wire under a nut and it cut through the sheath and split one of the strands. You can see the pic. Upon start-up, the air-bag service warning message came up on the dash. Obviously, I did something to cause this.

I'm trying to figure out if this cut wire is the cause? If there is a blown fuse? If the bad wire itself could be the cause?

First, what is this light green wire? I don't know for sure. This green wire runs from the Mid BEC relay center, which is mounted to the floor next to the parking break assembly. I've added a pic of the assembly (disassembled) to hopefully help you all decipher what I'm talking about. It runs to the brown connector. I also showed the wire cluster running behind the OBS plug - this is where it ran, and hopefully that'll help ID what this wire is as well. That wire cluster runs up to the left of the dash, around the cab fuse panel and up behind the dash somewhere. From my completely novice ability to decipher wiring diagrams, it seems this wire may run from that relay to the BCM (based on a Haynes diagram, I think I interpreted correctly).

Please note, the vehicle was started while the wire was pinched, and the strands were touching metal, so I'm assuming there was a short. I checked the Airbag fuse under the hood, and it was fine. One of the strands is cut, but only one. The truck runs and drives fine. During a short ride, I didn't notice any new things not working.

Any thoughts here? I'd really like to not have take this to a dealer since I know I'll get killed on cost this this was a DIY screwup.

My only thought - maybe the seat 30-amp breaker kicked and needs to be replaced? I do not have power seats.

Please let me know if you need more info and/or pic's and I'll provide what I can. Thanks in advance for all your help.

Doug_Scott · August 31, 2013

Here is what I would do. Start truck and take a volt meter, put positive lead on the wire that is cut open, negative lead on good ground. If you see battery voltage (approx. 12v), then I would think it did not blow fuse. If you do not see battery voltage there, look very carefully at the bare wire, use magnifying glass, to see if you can see any discolouration of the wire. If you can, chances are there is a blown fuse, or blown relay. I would then try to locate wiring diagram to see where the wire goes,

The above is done AFTER disconnecting battery and leaving it disconnected for a couple of minutes.

gmtech4 · August 31, 2013

Relay Block – I/P C3

Connector Part

Information

OEM: 15328768
Service: 89046826
Description: 12-Way F Metri-Pack 280 Series Flexlock (BN)

Terminal Part Information

Terminal/Tray: See Terminal Repair Kit
Core/Insulation Crimp: See Terminal Repair Kit
Release Tool/Test Probe: See Terminal Repair
Kit

Relay Block – I/P C3

Wire Color

Circuit No.

Function

A

L-GN

24

Backup Lamp Supply Voltage (DL3)

B

—

Not Used

C

BK

1050

Ground

D

D-BU/WH

149

Cargo Lamp Low Control

E

YE

1139

Ignition 1 Voltage

F

D-GN

2308

Passenger Air Bag Off Indicator Control (AL0)

G

BK/WH

1704

Low Reference (DF5)

H

D-BU

2307

Passenger Air Bag On Indicator Control (AL0)

J

L-BU

1620

CHMSL Supply Voltage

K

D-GN/WH

636

Ambient Air Temperature Sensor Signal (DF5)

L

GY/BK

690

Courtesy Lamp Supply Voltage

GY/BK

690

Courtesy Lamp Supply Voltage (YE9/Y91)

M

OG

1732

Inadvertent Power Supply Voltage

gmtech4 · August 31, 2013

not an air bag wire ,if its the light grn wire in terminal A ,its back up lamp supply voltage ...

i'd stop working on the truck now as you have no idea what you're doing ,,,,,you need to scan the air bag system ,,,,take it in ,dont touch it

you did something else ,,,,,

,tough question not so tough lol

sorry ,good luck

gmtech4 · August 31, 2013

Schmidty72 · August 31, 2013

govtech4,

I'm obviously not great with the electrical, but I have a healthy respect for any wires having to do with the air bag system. If I'm not mistake, that relay has a seat occupancy sensor go through it - is that correct (throuch C10)? If so, is is possible that a short from that wire killed one of the 2 breakers on that relay, and thus, the system is getting a fault code from that? I won't be upset if you just stick with your original comment to just get help. Been a crap day.

Cheers,

Schmidty

gmtech4 · August 31, 2013

govtech4,

I'm obviously not great with the electrical, but I have a healthy respect for any wires having to do with the air bag system. If I'm not mistake, that relay has a seat occupancy sensor go through it - is that correct (throuch C10)? If so, is is possible that a short from that wire killed one of the 2 breakers on that relay, and thus, the system is getting a fault code from that? I won't be upset if you just stick with your original comment to just get help. Been a crap day.

Cheers,

Schmidty

idk what you are talking about ,,,,,what relay ?,there are no breakers on a relay ,,,

signed very confused,Rob

truck needs to scanned by a real scanner,,,i'll help as much as possible ,,pics etc ,but i cant give experience lol

gmtech4 · September 1, 2013

Relay Block – I/P

C10

Connector Part

Information

OEM: 15357030
Service: 89046825
Description: 12-Way F Metri-Pack 280 Series Flex-Lock (NA)

Terminal Part Information

Terminal/Tray: See Terminal Repair Kit
Core/Insulation Crimp: See Terminal Repair Kit
Release Tool/Test Probe: See Terminal Repair
Kit

Relay Block – I/P C10

Pin

Wire Color

Circuit No.

Function

A–C

—

Not Used

D

D-GN

2308

Passenger Air Bag Off Indicator Control (AL0)

E

OG

1440

Battery Positive Voltage (AG2)

F

BN/WH

230

Instrument Panel Lamps Dimming Control (YE9 and Crew Cab)

BN/WH

230

Instrument Panel Lamps Dimming Control (YE9 and Crew Cab w/o Y91)

G

D-BU

2307

Passenger Air Bag On Indicator Control (AL0)

H

OG

1440

Battery Positive Voltage (AG1)

J

—

Not Used

K

OG

1340

Battery Positive Voltage (Crew Cab w/YE9)

L

PU

293

Rear Defog Element Supply Voltage (C49)

M

YE

1139

Ignition 1 Voltage (AL0)

YE

1139

Ignition 1 Voltage

Schmidty72 · September 1, 2013

My understanding is that what I have pictured is a "Power Distribution Center : MID BEC (Relay Center)". Your post shows that the wire, which I cut by accident, runs into "relay" block C3 (the term you posted), which corresponds to what I've found so far. That is why I referred to to that block as a relay. Sorry if that is the wrong terminology.

The breakdown of the inputs into relay block C3 were helpful (thank you), and confirmed my suspicions that the wire had nothing directly to do with the air bag system (based on what I could figure out from wiring diagrams myself so far). As I write this, you posted the info for C10, which I had found also, which shows that set of wires is very much related to the air bag system. I'm working under the assumption that the most likely explanation is the right one (and the first to figure out), and that is I cut a wire running into a power distribution center that is related to the airbags, and that is the cause of the problem.

There is a 30 and 25 amp breaker/fuse - they are the metal covered fuses, so again, sorry if they are not called breakers or fuses (or if they are actually neither, please tell me what they are). I'm wondering if something I did blew one of these fuses, and if that's part of the problem. I'm wondering if C3 and C10 are somehow connected electrically, and my screwup on C3 may have affected the systems running through C10? I am a novice, but that is why I posted this here. For me, a run to an autoparts store is not easy, so just getting a couple fuses to try out is a giant pain in the ass.

If I can't narrow this down to a fuse somewhere, then I'm beyond my comfort zone working with the airbag system and will be off to the deal for a scan. I'm not getting the multimeter out or taking apart any of the yellow connectors. My hope was that someone might have enough knowledge of the system to tell me if my screw-up (cutting into an likely shorting the wife for the backup lamps) could have affected something obvious and fixable (like a fuse).

If you can't go any further to help ont he topic, that's fine.

Cheers,

Schmidty

gmtech4 · September 1, 2013

find your owners manual and find the back up fuse ,check that ,if that is the only wire you hit then your chasing a ghost ,if you mounted the park brake mechanism wrong and pinched a harness (if possible idk) then that is the problem .

buy an Alldata account for $27 /yr

i wish i was there to see WTF ,lol

sry ,im no help ,,,check all fuses for SRS (air bag)

Schmidty72 · September 1, 2013

No worries, didn't necessarily expect an answer on this one...if I (or the mechanic) figures it out, I'll post the result.

rsoski · December 22, 2013

As my Gramps always told me….It ain't what we know that can hurt us….it is what we know for sure that ain't so!!!! We all tend to ASSUME we know the logic of a situation…..In reality …the air bag service light may be totally unrelated to your pinched wire. My bag light came on out of the blue….for no apparent reason. Although the timing may make you think the wire and the air bag service light are related…..don't assume ….

Doug_Scott · September 2, 2013

Another quick (and probably dumb question). I am correct, that if I "fixed" whatever was causing the airbag code, the code would go out on it's own correct? There is no need to have the code "cleared" by and SRS scanner?

I did find that I blew the TBC 2B fuse (which, from what I could find online, I'm figuring was related to the cut wire). After the first start, the service airbag message stayed up. Based on my limited knowledge of the systems related to TBC 2B, I had no expectation that this would solve the air bag problem, but I just thought I'd ask. Thanks.

If the issue is fixed, the code will clear itself after a number of engine starts. Pretty sure you can also get it to go out by disconnecting the battery. Battery clearance can be tight, so remove the negative lead. Reason for using the ground wire is that if the wrench slips while loosening the cable, it won't short the battery to ground.

And before the replies start about which cable to remove first, please have sound logic to your opinion.

Schmidty72 · September 1, 2013

Another quick (and probably dumb question). I am correct, that if I "fixed" whatever was causing the airbag code, the code would go out on it's own correct? There is no need to have the code "cleared" by and SRS scanner?

I did find that I blew the TBC 2B fuse (which, from what I could find online, I'm figuring was related to the cut wire). After the first start, the service airbag message stayed up. Based on my limited knowledge of the systems related to TBC 2B, I had no expectation that this would solve the air bag problem, but I just thought I'd ask. Thanks.