I just made a major mistake. Major big mess up.

I'm trying to run a power wire through the firewall for an amplifier. After reading on this forum, the best method seemed to be through the main wire harness on the firewall. I cut a slit like others said, and was able to stick a screw driver through. Great! Now I pulled the screw drive out, taped a pull string on it, and tried putting it back in. It got tight, and I pushed harder.

POP! (electrical short sounding)
HISSSS!!! (like pressurized air releasing from something)
Smoke. Not a lot. But some.


Now my airbag light is on. I drove it enough to back out of the garage in case it caught on fire. Didn't test everything out, but only the airbag light is on.


What on earth could that hissing sound have been? It came from the driver's footwell where the pop and smoke was from too.

 

i guess scan for codes and look for blown fuses to figrue out what wires need to get repaired. hopefully you did not take out some modules. like the SRS.

 

After a drive, everything works just fine except the sunroof and now the dash always says the hood is open. The sunroof turned out to just be the underhood fuse was blown, and after replacing it the sunroof works just fine.

I guess I have to finally bite the bullet and buy a Tech2 from ebay, but I'm still stumped on what the hissing sound could have been. I've let the magic smoke out of many electronics before, but I've never heard a slow hissing sound. Are airbag inflators held with a pressurized charge that could have released?

 

no. the airbag uses an explosive and detonator. but the module lives under the drivers seat on the floor.

 

Well I'm at a loss then. Just saw some really neat reviews for a VCX Nano that emulates and does everything a Tech2 does, as well as offering abilities to communicate with the newer GMs. Have one on order and will try it out next week. Fingers crossed.

And I've got an appointment at a stereo shop tomorrow for them to yank the power wire through that grommet. I'm done with that. Pissed.

 

Could be a capacitor was punctured or burnt out, possibly due to a cable short.

More investigation required, the clue is the airbag warning light, possibly the wiring going to it, if you can get the DTC.

 

I think you're right. I was wondering about capacitors and looked up some videos of people blowing them up on YouTube and I suspect that was the hissing noise. (this is nearly identical to it at the 29 second mark)

Also I found on a Duramax forum, some guy tried to rig up lights underhood by tapping into his hood open sensor, and in doing so blew out his BCM ... twice! The blown out BCM's only tell-tale was the constant HOOD OPEN message on the DIC. Everything else worked fine for him. My suspicions are now on I shorted something out in the BCM, which was the smoke and hissing. As for the airbag fault....dunno.

Code scanner arrives Tuesday.

 

The results are in! 1 code in the system for SRS: no communication with the front left impact sensor.

As for the hood, it just shows open. No codes.


I'm thinking my next step is to pull the BCM and see if I can confirm the capacitor went bad on it. As far as I know, that's the only electronic module behind the driver's knee panel, and that's where the sound and smoke came from. Unless anyone tells me otherwise.

 

@HellHoof
Assume this was B0100.

It would be tempting to swap impact sensors in case ones genuinely faulty, however a badly corroded sensor-bolt might present a risk.

Take care to disconnect the battery first to avoid the risk of accidental airbag deployment.

 

Actually B0083. It says Symptom 00, which I don't see any further explanation online for.

Anyway, I like your idea of swapping the sensors. I'll give that a try and see what happens.