Airbag System: How to Repair it

This is a quick how-to that I’m throwing together, after having had to replace & repair the airbag system on a mid 1990’s American car. This guide assumes that the airbags have deployed. This guide also assumes that the person using this guide may have never done something similar before, but nevertheless somewhat handy! Also, use this guide at your own risk; one could get injured if the airbags are accidentally deployed, while working near the airbags!

  1. If the airbags have already been deployed, then there is no safety concern while removing the bags/module. However, if the airbags haven’t been deployed, or when you are trying to install new bags/module/cables then you’d want to remove the negative terminal from the battery, and remove the airbag fuse. This way, you can’t accidentally deploy the airbags while working. Also, the airbags have supposedly another power source that is designed to kick in immediately, in case of a battery failure during an accident. This reserve system, would bleed while the battery is disconnected. Thus it will bleed while you are working on removing the dash-board, the airbags, and the airbag module (under the passenger seat).
  2. Under the steering wheel column, on the left just on the edge inside the plastic cover (Clock spring replacement), there are 2 yellow connectors. One is for the passenger airbag, and the other connector is for the driver airbag. Disconnect both connectors. These are tricky yellow connectors. Do not break them as you try to disconnect them (or any other airbag yellow connector). In all the yellow airbag connectors, most (if not all) have 2 safety features: First, the connectors have some kind of fail-safe mechanism that prevents the connectors from ever being disconnected accidentally. Second, the connectors would have this plastic ledge (they are colored black, blue, grey, red, or orange. Or maybe even some other color in other cars). These plastic ledges are used to “open-circuit” the connectors, once plugged, thus making them functional. If those ledges are not inserted or they are melted/damaged, then the airbag system would detect a short somewhere and thus flag the warning sign in the instrument panel (How to install a clock spring).
  3. Remove the dash-board. I followed the Haynes manual for this: First remove the “arc” looking piece of plastic that is placed between the windshield (inside the car) and the dash-board. It sits just in front of the center vent on the top side of the dash-board. There are no screws. There are some (not visible from the top) latches that would ledge onto some receptors. Just wiggle this “arc” a bit and it will start to come off. As you remove it, be careful not to scratch your dash-board with the metallic ledges that are now free & exposed.
  4. Start removing all the bolts/screws that you see (I think ~10+). You’ll also need to remove the radio/AC plastic cover panel along with a metal frame that covers the latch for the glove compartment.
  5. Now, iirc, the venting ducts may cover some of the bolts/screws that attach the passenger sire airbag. Look for four screws (2 on the top & 2 on the bottom) on the passenger airbags, and remove anything else that blocks your access to these four screws.
  6. Remove the passenger side airbag, it’s big and heavy. If you don’t have your replacement airbags, then you can put back the dash-board and all, if you chose to drive your car AT YOUR OWN RISK while you await your replacement airbags.
  7. By unscrewing the 2 bolts in the back of the steering wheel, the driver airbag would be removed. If the driver airbag is deployed, you can just cut the bag out, thus you can put back the now empty airbag housing. This way you can at least drive your car AT YOUR OWN RISK. Make sure the horn works.
  8. Before putting back the now-empty driver airbag module, we need to check if the clock spring (SIR coil) is damaged or not. Often, if the driver airbag got deployed, the wires in the clock spring could overheat (from the high current needed to deploy the airbags) and the copper wires might break. So, we need to check if the wires in the clock spring are damaged or not. Now, from the steering wheel, follow the airbag yellow cable down to the bottom left side of the steering column, and find the connector (you should have unplugged in step 2) and check for damage. Now, with a digital multi-meter, check the connector (in the steering wheel) for open/short (How to test a clock spring). My clock spring wasn’t damaged, so luckily I didn’t need to replace the clock spring. The Haynes manual shows how to remove & replace the clock spring (SIR coil). You can find used ones on eBay for ~$40.
  9. Go buy yourself some used airbags (driver and/or passenger, which ever got deployed. Usually both). I got a used driver and passenger airbag; both for $25, shipped on eBay. So look around there is no need to pay in the hundreds of dollars!
  10. Once the vehicle gets into a crash that deploys the airbags; the airbag module (located under the front passenger seat; for most cars) would get set/flagged, and the airbag warning light would come on; on the instrument panel (Note, the warning light could also come on for other failures within the airbag system). The job of the airbag module is to record speed data, and would store the last 1 minute of data immediate to before a crash. Once the airbags get deployed, then the airbag module gets set/flagged. So even if you replace the airbags and (if needed) the clock spring (SIR coil), you still have to replace/repair the airbag module. The module could either be replaced or reprogrammed; I’ll get into that later. First you need to remove the front passenger seat. Remove the 4 bolts holding down the seat, and then remove the seat (it might be a good time to pass the vacuum cleaner!). The airbag module is hidden under the carpet. Usually there is a small opening in the carpet that allows you to see the module. However, the opening is not big enough to remove the module. You can either choose to remove the carpet (I don’t know how), or if you don’t care like me, just cut the carpet just enough to remove the airbag module. On a side note, the car would drive fine with the airbags and module removed. You just don’t have any protection in the event of a a collision.
  11. Now that you have removed the airbag module, you can either buy a used replacement for ~$50, or have your own unit reprogrammed, also for ~$50. I chose the latter. I sent my unit to myairbags. They also have an eBay store. On a side note, for newer cars, and for some other car manufacturers, some car specific data is also stored in the airbag module. Thus, having your own airbag module reprogrammed is a better solution than buying a used one, where the embedded codes wouldn’t match your vehicle’s; if the module is obtained from another used vehicle.
  12. Now, if you don’t have the replacement parts ready, keep the airbags and the airbag module out (so you can look up the part number to order. Also they are pretty useless now, being deployed), and put back the dash-board, the empty driver airbag housing in the steering wheel (so you can use the horn), and connect the negative battery terminal. You can leave the airbag fuse out, or plug it back in if you don’t want to lose it. If you keep the airbag fuse out, the seat belt warning light would stay on.
  13. After you get all of your replacement parts and are ready to install, first; again remove the negative battery terminal.
  14. Remove the airbag fuse.
  15. While you’re working on removing the dash-board and the front passenger seat, the reserve power source would bleed (see step 1).
  16. Install the passenger airbag, and plug the connector.
  17. Install the driver airbag, and plug the connector.
  18. Install the airbag module (under the passenger seat), and plug the connector.
  19. Plug both connectors that are under the steering column on the left side (see step 2).
  20. Plug the airbag fuse.
  21. Connect the negative terminal back onto the battery.
  22. Start your car. If all is good, then the airbag warning sign on the instrument panel would flash (7 times I think), then disappear. If the warning sign is still on, then something’s amiss!
  23. Turn off your engine, and put back the dash-board and the passenger seat. Then go celebrate for saving hundreds of dollars, and for a job well done!

Some helpful videos:
How to test a clock spring


Clock spring replacement


How to install a clock spring

I hope I didn’t miss anything!

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