Airbag light on

[zieg85]

My airbag light is on all the time on my 2001 C2500HD.  Is there any diagnosis procedures written or will an OBD2 scanner tell me anything.  I hear there is a big airbag recall but have no idea if my truck is part of it.  I would be happy to just unhook the system but it is a supposed safety feature.  Looking for direction shy of taking it to the dealership if at all possible.

When I was test driving the truck the light would be on most the time then shut off for a bit then turn back on.  It doesn't matter if the passenger airbag is switched off or not with the light being or staying on.

[Irish_Alley]

when i first saw "Airbag light on" i was thinking who is smoking what. then it hit me there're other trucks out there besides 73-87 lol. cant help you but kind of interested if there is a diagnosis for this problem

[philo_beddoe]

My 77 aint got no airbag, missed another recall.

[LTZ C20]

Ok Zieg, I'll help ya out here too.

First off, I haven't heard anything at work about those older trucks being involved in any airbag recalls. I could be wrong, but I highly doubt it, so probably no need to worry there. Even if it was part of the recall, then the recalls are free anyway.

Now, you can read airbag codes with an OBD2 scanner, but only if the scanner supports reading airbag codes. There are some other things you can do to try any fix it. There are a number of things that can happen and are failry easy to check. Here's what could be going on:

1-connectors somewhere are dirty (we see this sometimes with trucks that are farm or work truck or people who use the truck alot in less urban areas)
2-a sensor, switch or module has failed
3-a wire has chaffed thru somewhere and shorted to ground (we see this sometimes also for the same reason as possibility 1)

Now here's how to check these things. Notice the order to check these is 1, 3, 2. Not 1, 2, 3. There is a reason for that, 1 and 3 are easiest to check first before 2.

OFTEN, BUT NOT ALWAYS, AIRBAG CONNECTOR BODIES ARE YELLOW IN COLOR TO SHOW YOU THEY ARE FOR THE AIRBAG SYSTEM.

1- dirt likes to work it's way into connectors one trucks that are used in truck worthy environments. There are 2 impact sensors behind the bumper, you should be able to get to them from the bottom with a creaper. With ign off, unplug both sensors and check to make sure both sensor contacts and connector contacts are clean and dry. If so, apply just a pinch of dielectric grease to each terminal on the female side. It's easiest use dielectric grease that comes in the small tube with the little tip on it like rtv silicone. Just put the end of the grease tube against each contact in the female side, squeeze just a pinch of grease into each terminal. Then reconnect both sensors. If they are dirty, clean with electrical contact cleaner until completely clean, then lube as described and reconnect. Do a quick check of the harnesses to see if anything is dammaged or rubbed thru. Then start the truck and see if the light goes out and stays out. If it does then that's possible the fault could have been there.

3- under the drivers sill plate trim there are wires that get packed with dirt same as possibility one, but they also get stepped on alot under the sill plate because it's a sill plate, this area gets packed with dirt and the wire being ground down by the dirt, get rubbed against metal and can chaff and short to ground. Especially if the sill plate is broken or cracked! Remove the plate, the trim around the hood release handle and the trim on the b pillar in the back corner of the cab. The trim pieces just snap into position. Once you pull the sill off you will understand how the snaps work and how much pressure you have to apply to get them free. With the ign off again, make sure this area is clean and free from dirt, mud, debris, examine all wiring, check for shorts or chaffs, and check connectors for dirt again here. If dirty connectors are found, clean as above. If any wires are found chaffed, you will need to repair properly with solder. If they are chaffed pretty bad, it might be better to cut out the damaged area, solder in new wires, heat shrink solders and rewrap harness with electrical or even better abrasion tape. Once you have done the drivers side, remove the same trim pieces on the passanger side and check those areas just as you did the drivers side, correct any faults you find. Also check under the drivers seat for dirty connectors and damaged wires. There is a sensor in the seat to tell the module you are sitting in the truck. With any problems corrected, start the truck and see what the lite goes and stays out. If so, the fault could have been were you just checked.

2- There is a possibility that a sensor, switch or the Airbag module has failed and will need to be replaced. We can address that if needed. If, during your checks of 1 and 3, you find a sensor or part physically damaged, then you should replace as necessary with GM parts, i.e. you check the front airbag sensors and 1 of them is broken or cracked or damaged somehow.

The reason the lite goes out is that the code stops setting if you were able to fix or you found an issue and it goes into history so the light turns off until the code sets current again.

This is the best you can do unless you can pull a code (or codes) in which case that obviously makes things a heck of a lot easier.

So scan if you can and report back. If you can't scan, investigate and report back. Also, I can answer questions too with pictures, so if you have a question about something post a pic.

Now to put my thumbs on ice and take some joint supplements, I think I typed my fingers off.

[zieg85]

Thanks so much.  Another case of going above and beyond LTZ C20!... Awesome!!!

[LTZ C20]

Your welcome. As soon as I saw this I knew I could help cuz I've seen a hand few of these cases before at work.

[zieg85]

#3 got me to thinking.  Either the seat belt light is somehow disconnected or the sensor is unplugged.  This truck doesn't care if you are not belted in, no chimes or lights.  I will report my findings for sure

[LTZ C20]

#3 got me to thinking.  Either the seat belt light is somehow disconnected or the sensor is unplugged.  This truck doesn't care if you are not belted in, no chimes or lights.  I will report my findings for sure

Those early 2000 models are kinda funny like that, I've noticed that before. Sometimes the light will be on, sometimes it won't. Even if you buckle it and then unbuckle it, the light doesn't come on. It's something to check tho because the seat belts are tied into the Airbag system, the only purpose of the seat belt light is to tell you to put it on, any faults with belts that set a code in the computer will turn the Airbag light on. Really would do alot if you could pull codes.

[zieg85]

Small update, only code my reader pulled was a clutch fault, yellow light and the check engine light wasn't set.  Will look at the connections next

[LTZ C20]

That means your code reader doesn't support airbag codes

[zieg85]

That means your code reader doesn't support airbag codes

I figured that was the case.  Did find out the seat belt light plug under the seat was disconnected.  I reconnected it and the light now works but nothing has changed.  Will pulling the air bag fuse cause it not to run?

[LTZ C20]

Cause what not to run? You mean cause the airbag system to be disabled?

[zieg85]

Cause what not to run? You mean cause the airbag system to be disabled?

Cause the truck not to run? Like a safety feature that can't be disconnected?

[LTZ C20]

Oh nope, it will run if you rip the entire air bag system out.

[zieg85]

Oh nope, it will run if you rip the entire air bag system out.

Will removing the fuse shut the light out?